diff --git a/ompi/mca/coll/portals4/Makefile.am b/ompi/mca/coll/portals4/Makefile.am
index 444ebf237d..5d6a9faa15 100644
--- a/ompi/mca/coll/portals4/Makefile.am
+++ b/ompi/mca/coll/portals4/Makefile.am
@@ -15,6 +15,7 @@ local_sources = \
 	coll_portals4_barrier.c \
 	coll_portals4_bcast.c \
 	coll_portals4_reduce.c \
+	coll_portals4_gather.c \
 	coll_portals4_request.h \
 	coll_portals4_request.c
 
diff --git a/ompi/mca/coll/portals4/coll_portals4.h b/ompi/mca/coll/portals4/coll_portals4.h
index c23b4d088b..4eb631e222 100644
--- a/ompi/mca/coll/portals4/coll_portals4.h
+++ b/ompi/mca/coll/portals4/coll_portals4.h
@@ -24,13 +24,18 @@
 #include "ompi/datatype/ompi_datatype_internal.h"
 #include "ompi/op/op.h"
 #include "ompi/mca/mca.h"
+#include "opal/datatype/opal_convertor.h"
 #include "ompi/mca/coll/coll.h"
 #include "ompi/request/request.h"
 #include "ompi/communicator/communicator.h"
 #include "ompi/mca/coll/base/base.h"
+#include "ompi/datatype/ompi_datatype.h"
+#include "ompi/mca/mtl/portals4/mtl_portals4_endpoint.h"
 
 #include "ompi/mca/mtl/portals4/mtl_portals4.h"
 
+#define MAXTREEFANOUT 32
+
 BEGIN_C_DECLS
 
 #define COLL_PORTALS4_NO_OP ((ptl_op_t)-1)
@@ -61,10 +66,27 @@ struct mca_coll_portals4_component_t {
 
     ptl_ni_limits_t ni_limits;
 
+    int use_binomial_gather_algorithm;
+
 };
 typedef struct mca_coll_portals4_component_t mca_coll_portals4_component_t;
 OMPI_MODULE_DECLSPEC extern mca_coll_portals4_component_t mca_coll_portals4_component;
 
+
+/*
+ * Borrowed with thanks from the coll-tuned component, then modified for Portals4.
+ */
+typedef struct ompi_coll_portals4_tree_t {
+    int32_t tree_root;
+    int32_t tree_fanout;
+    int32_t tree_bmtree;
+    int32_t tree_prev;
+    int32_t tree_next[MAXTREEFANOUT];
+    int32_t tree_nextsize;
+    int32_t tree_numdescendants;
+} ompi_coll_portals4_tree_t;
+
+
 struct mca_coll_portals4_module_t {
     mca_coll_base_module_t super;
     size_t coll_count;
@@ -79,6 +101,13 @@ struct mca_coll_portals4_module_t {
     mca_coll_base_module_t *previous_allreduce_module;
     mca_coll_base_module_iallreduce_fn_t previous_iallreduce;
     mca_coll_base_module_t *previous_iallreduce_module;
+
+    /* binomial tree */
+    ompi_coll_portals4_tree_t *cached_in_order_bmtree;
+    int                        cached_in_order_bmtree_root;
+
+    size_t barrier_count;
+    size_t gather_count;
 };
 typedef struct mca_coll_portals4_module_t mca_coll_portals4_module_t;
 OBJ_CLASS_DECLARATION(mca_coll_portals4_module_t);
@@ -135,6 +164,22 @@ int
 opal_stderr(const char *msg, const char *file,
         const int line, const int ret);
 
+/*
+ * Borrowed with thanks from the coll-tuned component.
+ */
+#define COLL_PORTALS4_UPDATE_IN_ORDER_BMTREE( OMPI_COMM, PORTALS4_MODULE, ROOT ) \
+do {                                                                                         \
+    if( !( ((PORTALS4_MODULE)->cached_in_order_bmtree)                                               \
+           && ((PORTALS4_MODULE)->cached_in_order_bmtree_root == (ROOT)) ) ) {                       \
+        if( (PORTALS4_MODULE)->cached_in_order_bmtree ) { /* destroy previous binomial if defined */ \
+            ompi_coll_portals4_destroy_tree( &((PORTALS4_MODULE)->cached_in_order_bmtree) );       \
+        }                                                                                    \
+        (PORTALS4_MODULE)->cached_in_order_bmtree = ompi_coll_portals4_build_in_order_bmtree( (OMPI_COMM), (ROOT) ); \
+        (PORTALS4_MODULE)->cached_in_order_bmtree_root = (ROOT);                                     \
+    }                                                                                        \
+} while (0)
+
+
 int ompi_coll_portals4_barrier_intra(struct ompi_communicator_t *comm,
         mca_coll_base_module_t *module);
 int ompi_coll_portals4_ibarrier_intra(struct ompi_communicator_t *comm,
@@ -177,6 +222,20 @@ int ompi_coll_portals4_iallreduce_intra(const void* sendbuf, void* recvbuf, int
 int
 ompi_coll_portals4_iallreduce_intra_fini(struct ompi_coll_portals4_request_t *request);
 
+int ompi_coll_portals4_gather_intra(const void *sbuf, int scount, struct ompi_datatype_t *sdtype,
+                                    void *rbuf, int rcount, struct ompi_datatype_t *rdtype,
+                                    int root,
+                                    struct ompi_communicator_t *comm,
+                                    mca_coll_base_module_t *module);
+int ompi_coll_portals4_igather_intra(const void *sbuf, int scount, struct ompi_datatype_t *sdtype,
+                                     void *rbuf, int rcount, struct ompi_datatype_t *rdtype,
+                                     int root,
+                                     struct ompi_communicator_t *comm,
+                                     ompi_request_t **request,
+                                     mca_coll_base_module_t *module);
+int ompi_coll_portals4_igather_intra_fini(struct ompi_coll_portals4_request_t *request);
+
+
 static inline ptl_process_t
 ompi_coll_portals4_get_peer(struct ompi_communicator_t *comm, int rank)
 {
@@ -357,6 +416,43 @@ void get_k_ary_tree(const unsigned int k_ary,
     return;
 }
 
+
+static inline void
+ompi_coll_portals4_create_recv_converter (opal_convertor_t *converter,
+                                          void *target,
+                                          ompi_proc_t *proc,
+                                          int count,
+                                          ompi_datatype_t *datatype)
+{
+    /* create converter */
+    OBJ_CONSTRUCT(converter, opal_convertor_t);
+
+    /* initialize converter */
+    opal_convertor_copy_and_prepare_for_recv(proc->super.proc_convertor,
+                                             &datatype->super,
+                                             count,
+                                             target,
+                                             0,
+                                             converter);
+}
+
+static inline void
+ompi_coll_portals4_create_send_converter (opal_convertor_t *converter,
+                                          const void *source,
+                                          ompi_proc_t *proc,
+                                          int count,
+                                          ompi_datatype_t *datatype)
+{
+    OBJ_CONSTRUCT(converter, opal_convertor_t);
+
+    opal_convertor_copy_and_prepare_for_send(proc->super.proc_convertor,
+                                             &datatype->super,
+                                             count,
+                                             source,
+                                             0,
+                                             converter);
+}
+
 END_C_DECLS
 
 #endif /* MCA_COLL_PORTALS4_EXPORT_H */
diff --git a/ompi/mca/coll/portals4/coll_portals4_component.c b/ompi/mca/coll/portals4/coll_portals4_component.c
index 73eebef24a..679d55ad32 100644
--- a/ompi/mca/coll/portals4/coll_portals4_component.c
+++ b/ompi/mca/coll/portals4/coll_portals4_component.c
@@ -203,6 +203,14 @@ portals4_register(void)
             MCA_BASE_VAR_SCOPE_READONLY,
             &mca_coll_portals4_priority);
 
+    mca_coll_portals4_component.use_binomial_gather_algorithm = 0;
+    (void) mca_base_component_var_register(&mca_coll_portals4_component.super.collm_version, "use_binomial_gather_algorithm",
+            "if 1 use a binomial tree algorithm for gather, otherwise use linear",
+            MCA_BASE_VAR_TYPE_INT, NULL, 0, 0,
+            OPAL_INFO_LVL_9,
+            MCA_BASE_VAR_SCOPE_READONLY,
+            &mca_coll_portals4_component.use_binomial_gather_algorithm);
+
     return OMPI_SUCCESS;
 }
 
@@ -463,7 +471,7 @@ portals4_init_query(bool enable_progress_threads,
                 __FILE__, __LINE__, ret);
         return OMPI_ERROR;
     }
-    OPAL_OUTPUT_VERBOSE((90, ompi_coll_base_framework.framework_output, "PtlMDBind start=%p length=%x\n", md.start, md.length));
+    OPAL_OUTPUT_VERBOSE((90, ompi_coll_base_framework.framework_output, "PtlMDBind start=%p length=%lx\n", md.start, md.length));
 
     /* setup finish ack ME */
     me.start = NULL;
@@ -472,7 +480,7 @@ portals4_init_query(bool enable_progress_threads,
     me.min_free = 0;
     me.uid = mca_coll_portals4_component.uid;
     me.options = PTL_ME_OP_PUT |
-            PTL_ME_EVENT_LINK_DISABLE | PTL_ME_EVENT_UNLINK_DISABLE;
+        PTL_ME_EVENT_LINK_DISABLE | PTL_ME_EVENT_UNLINK_DISABLE;
     me.match_id.phys.nid = PTL_NID_ANY;
     me.match_id.phys.pid = PTL_PID_ANY;
     me.match_bits = 0;
@@ -584,6 +592,12 @@ portals4_comm_query(struct ompi_communicator_t *comm,
     portals4_module->super.coll_barrier = ompi_coll_portals4_barrier_intra;
     portals4_module->super.coll_ibarrier = ompi_coll_portals4_ibarrier_intra;
 
+    portals4_module->super.coll_gather   = ompi_coll_portals4_gather_intra;
+    portals4_module->super.coll_igather  = ompi_coll_portals4_igather_intra;
+
+    portals4_module->cached_in_order_bmtree=NULL;
+    portals4_module->cached_in_order_bmtree_root=-1;
+
     portals4_module->super.coll_bcast = ompi_coll_portals4_bcast_intra;
     portals4_module->super.coll_ibcast = ompi_coll_portals4_ibcast_intra;
 
@@ -593,6 +607,9 @@ portals4_comm_query(struct ompi_communicator_t *comm,
     portals4_module->super.coll_reduce = ompi_coll_portals4_reduce_intra;
     portals4_module->super.coll_ireduce = ompi_coll_portals4_ireduce_intra;
 
+    portals4_module->barrier_count = 0;
+    portals4_module->gather_count = 0;
+
     return &(portals4_module->super);
 }
 
@@ -689,9 +706,11 @@ portals4_progress(void)
                         ompi_coll_portals4_iallreduce_intra_fini(ptl_request);
                         break;
                     case OMPI_COLL_PORTALS4_TYPE_SCATTER:
-                    case OMPI_COLL_PORTALS4_TYPE_GATHER:
                         opal_output(ompi_coll_base_framework.framework_output,
-                                "allreduce is not supported yet\n");
+                                "scatter is not supported yet\n");
+                        break;
+                    case OMPI_COLL_PORTALS4_TYPE_GATHER:
+                        ompi_coll_portals4_igather_intra_fini(ptl_request);
                         break;
                     }
                 }
diff --git a/ompi/mca/coll/portals4/coll_portals4_gather.c b/ompi/mca/coll/portals4/coll_portals4_gather.c
new file mode 100644
index 0000000000..9cde2d2bd9
--- /dev/null
+++ b/ompi/mca/coll/portals4/coll_portals4_gather.c
@@ -0,0 +1,1326 @@
+/*
+ * Copyright (c) 2015      Sandia National Laboratories. All rights reserved.
+ * $COPYRIGHT$
+ * 
+ * Additional copyrights may follow
+ * 
+ * $HEADER$
+ */
+
+
+#include "ompi_config.h"
+
+#include "mpi.h"
+#include "ompi/constants.h"
+#include "ompi/datatype/ompi_datatype.h"
+#include "opal/util/bit_ops.h"
+#include "ompi/mca/pml/pml.h"
+#include "ompi/mca/coll/coll.h"
+#include "ompi/mca/coll/base/base.h"
+
+#include "coll_portals4.h"
+#include "coll_portals4_request.h"
+
+
+#undef RTR_USES_TRIGGERED_PUT
+
+
+#define VRANK(ra, ro, si) ((ra - ro + si) % si)
+
+/*
+ * Borrowed with thanks from the coll-tuned component, then modified for Portals4.
+ *
+ *
+ * Constructs in-order binomial tree which can be used for gather/scatter
+ * operations.
+ *
+ * Here are some of the examples of this tree:
+ * size = 2                    size = 4                 size = 8
+ *      0                           0                        0
+ *     /                          / |                      / | \
+ *    1                          1  2                     1  2  4
+ *                                  |                        |  | \
+ *                                  3                        3  5  6
+ *                                                                 |
+ *                                                                 7
+ *
+ * size = 16
+ *      0
+ *    / | \        \
+ *   1  2  4        8
+ *      |  | \    / | \
+ *      3  5  6  9  10 12
+ *            |     |  | \
+ *            7     11 13 14
+ *                        |
+ *                        15
+ */
+static ompi_coll_portals4_tree_t*
+ompi_coll_portals4_build_in_order_bmtree( struct ompi_communicator_t* comm,
+                                            int root )
+{
+    int childs = 0, rank, vrank, vparent, size, mask = 1, remote, i;
+    ompi_coll_portals4_tree_t *bmtree;
+
+    /*
+     * Get size and rank of the process in this communicator
+     */
+    size = ompi_comm_size(comm);
+    rank = ompi_comm_rank(comm);
+
+    vrank = VRANK(rank, root, size);
+
+    bmtree = (ompi_coll_portals4_tree_t*)malloc(sizeof(ompi_coll_portals4_tree_t));
+    if (!bmtree) {
+        opal_output(ompi_coll_base_framework.framework_output,
+                    "coll:portals4:build_bmtree PANIC out of memory");
+        return NULL;
+    }
+
+    bmtree->tree_bmtree   = 1;
+    bmtree->tree_root     = MPI_UNDEFINED;
+    bmtree->tree_nextsize = MPI_UNDEFINED;
+    for(i=0;i<MAXTREEFANOUT;i++) {
+        bmtree->tree_next[i] = -1;
+    }
+
+    if (root == rank) {
+        bmtree->tree_prev = root;
+    }
+
+    while (mask < size) {
+        remote = vrank ^ mask;
+        if (remote < vrank) {
+            bmtree->tree_prev = (remote + root) % size;
+            break;
+        } else if (remote < size) {
+            bmtree->tree_next[childs] = (remote + root) % size;
+            childs++;
+            if (childs==MAXTREEFANOUT) {
+                opal_output(ompi_coll_base_framework.framework_output,
+                             "coll:portals4:build_bmtree max fanout incorrect %d needed %d",
+                             MAXTREEFANOUT, childs);
+                return NULL;
+            }
+        }
+        mask <<= 1;
+    }
+    bmtree->tree_nextsize = childs;
+    bmtree->tree_root     = root;
+
+    vparent = VRANK(bmtree->tree_prev, root, size);
+    if (root == rank) {
+        bmtree->tree_numdescendants = size - 1;
+    } else if (bmtree->tree_nextsize > 0) {
+        int possible_descendants = vrank - vparent - 1;
+        if ((vrank + possible_descendants) > size) {
+            bmtree->tree_numdescendants = size - vrank - 1;
+        } else {
+            bmtree->tree_numdescendants = possible_descendants;
+        }
+    } else {
+        bmtree->tree_numdescendants = 0;
+    }
+
+    opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                        "%d: bmtree result - size(%d)  rank(%d)  vrank(%d)  root(%d)  parent(%d) vparent(%d)  numkids(%d)  numdescendants(%d)",
+                        __LINE__,
+                        size, rank, vrank, bmtree->tree_root, bmtree->tree_prev, vparent, bmtree->tree_nextsize, bmtree->tree_numdescendants);
+
+    return bmtree;
+}
+
+/*
+ * Borrowed with thanks from the coll-tuned component.
+ */
+static int
+ompi_coll_portals4_destroy_tree( ompi_coll_portals4_tree_t** tree )
+{
+    ompi_coll_portals4_tree_t *ptr;
+
+    if ((!tree)||(!*tree)) {
+        return OMPI_SUCCESS;
+    }
+
+    ptr = *tree;
+
+    free (ptr);
+    *tree = NULL;   /* mark tree as gone */
+
+    return OMPI_SUCCESS;
+}
+
+
+static int
+setup_gather_buffers_binomial(struct ompi_communicator_t   *comm,
+                              ompi_coll_portals4_request_t *request,
+                              mca_coll_portals4_module_t   *portals4_module)
+{
+    int ret, line;
+
+    uint32_t iov_count = 1;
+    struct iovec iov;
+    size_t max_data;
+
+    ompi_coll_portals4_tree_t* bmtree = portals4_module->cached_in_order_bmtree;
+
+    int vrank = VRANK(request->u.gather.my_rank, request->u.gather.root_rank, request->u.gather.size);
+
+    ompi_coll_portals4_create_send_converter (&request->u.gather.send_converter,
+                                              request->u.gather.pack_src_buf + request->u.gather.pack_src_offset,
+                                              ompi_comm_peer_lookup(comm, request->u.gather.my_rank),
+                                              request->u.gather.pack_src_count,
+                                              request->u.gather.pack_src_dtype);
+    opal_convertor_get_packed_size(&request->u.gather.send_converter, &request->u.gather.packed_size);
+
+    /**********************************/
+    /* Setup Gather Buffers           */
+    /**********************************/
+    if (vrank == 0) {
+        request->u.gather.unpack_bytes=
+            request->u.gather.unpack_dst_true_extent +
+            ((ptrdiff_t)request->u.gather.unpack_dst_count * (ptrdiff_t)request->u.gather.size - 1) * request->u.gather.unpack_dst_extent;
+
+        request->u.gather.gather_bytes=request->u.gather.packed_size * (ptrdiff_t)request->u.gather.size;
+
+        /*
+         * root node, needs to allocate temp buffer to gather
+         * packed bytes from all nodes including self.
+         * rotate will occur after transfer during unpack.
+         */
+        request->u.gather.gather_buf = (char *) malloc(request->u.gather.gather_bytes);
+        if (NULL == request->u.gather.gather_buf) {
+            ret = OMPI_ERR_OUT_OF_RESOURCE; line = __LINE__; goto err_hdlr;
+        }
+        request->u.gather.free_after = 1;
+
+        /* pack local data into request->u.gather.gather_buf */
+        iov.iov_len = request->u.gather.gather_bytes;
+        iov.iov_base = (IOVBASE_TYPE *) request->u.gather.gather_buf;
+        opal_convertor_pack(&request->u.gather.send_converter, &iov, &iov_count, &max_data);
+
+        opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                            "%s:%d:vrank(%d): root - gather_buf(%p) - gather_bytes(%lu)=packed_size(%ld) * size(%d)",
+                            __FILE__, __LINE__, vrank,
+                            request->u.gather.gather_buf, request->u.gather.gather_bytes,
+                            request->u.gather.packed_size, request->u.gather.size);
+    } else if (bmtree->tree_nextsize) {
+        /*
+         * other non-leaf nodes, allocate temp buffer to receive data from
+         * children.  we need space for data from tree_numdescendants + 1
+         * processes.
+         */
+        request->u.gather.gather_bytes=request->u.gather.packed_size * ((ptrdiff_t)bmtree->tree_numdescendants + 1);
+
+        request->u.gather.gather_buf = (char *) malloc(request->u.gather.gather_bytes);
+        if (NULL == request->u.gather.gather_buf) {
+            ret = OMPI_ERR_OUT_OF_RESOURCE; line = __LINE__; goto err_hdlr;
+        }
+        request->u.gather.free_after = 1;
+
+        iov.iov_len = request->u.gather.gather_bytes;
+        iov.iov_base = (IOVBASE_TYPE *) request->u.gather.gather_buf;
+        opal_convertor_pack(&request->u.gather.send_converter, &iov, &iov_count, &max_data);
+
+        opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                            "%s:%d:vrank(%d): nonleaf - gather_buf(%p) - gather_bytes(%lu)=packed_size(%ld) * (bmtree->tree_numdescendants(%d) + 1)",
+                            __FILE__, __LINE__, vrank,
+                            request->u.gather.gather_buf, request->u.gather.gather_bytes,
+                            request->u.gather.packed_size, bmtree->tree_numdescendants);
+    } else {
+        /* leaf nodes, allocate space to pack into and put from */
+        request->u.gather.gather_bytes=request->u.gather.packed_size;
+
+        request->u.gather.gather_buf = (char *) malloc(request->u.gather.gather_bytes);
+        if (NULL == request->u.gather.gather_buf) {
+            ret = OMPI_ERR_OUT_OF_RESOURCE; line = __LINE__; goto err_hdlr;
+        }
+        request->u.gather.free_after = 1;
+
+        iov.iov_len = request->u.gather.gather_bytes;
+        iov.iov_base = (IOVBASE_TYPE *) request->u.gather.gather_buf;
+        opal_convertor_pack(&request->u.gather.send_converter, &iov, &iov_count, &max_data);
+
+        opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                            "%s:%d:vrank(%d): leaf - gather_buf(%p) - gather_bytes(%lu)=packed_size(%ld)",
+                            __FILE__, __LINE__, vrank,
+                            request->u.gather.gather_buf, request->u.gather.gather_bytes,
+                            request->u.gather.packed_size);
+    }
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    opal_output(ompi_coll_base_framework.framework_output,
+                "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+                __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+static int
+setup_gather_buffers_linear(struct ompi_communicator_t   *comm,
+                            ompi_coll_portals4_request_t *request,
+                            mca_coll_portals4_module_t   *portals4_module)
+{
+    int ret, line;
+
+    uint32_t iov_count = 1;
+    struct iovec iov;
+    size_t max_data;
+
+    int8_t i_am_root = (request->u.gather.my_rank == request->u.gather.root_rank);
+
+    ompi_coll_portals4_create_send_converter (&request->u.gather.send_converter,
+                                              request->u.gather.pack_src_buf + request->u.gather.pack_src_offset,
+                                              ompi_comm_peer_lookup(comm, request->u.gather.my_rank),
+                                              request->u.gather.pack_src_count,
+                                              request->u.gather.pack_src_dtype);
+    opal_convertor_get_packed_size(&request->u.gather.send_converter, &request->u.gather.packed_size);
+
+    /**********************************/
+    /* Setup Gather Buffers           */
+    /**********************************/
+    if (i_am_root) {
+        request->u.gather.unpack_bytes=
+            request->u.gather.unpack_dst_true_extent +
+            ((ptrdiff_t)request->u.gather.unpack_dst_count * (ptrdiff_t)request->u.gather.size - 1) * request->u.gather.unpack_dst_extent;
+
+        request->u.gather.gather_bytes=request->u.gather.packed_size * (ptrdiff_t)request->u.gather.size;
+
+        /*
+         * root node, needs to allocate temp buffer to gather
+         * packed bytes from all nodes including self.
+         */
+        request->u.gather.gather_buf = (char *) malloc(request->u.gather.gather_bytes);
+        if (NULL == request->u.gather.gather_buf) {
+            ret = OMPI_ERR_OUT_OF_RESOURCE; line = __LINE__; goto err_hdlr;
+        }
+        request->u.gather.free_after = 1;
+
+        /* pack local data into request->u.gather.gather_buf */
+        uint64_t gather_buf_offset = (ptrdiff_t)request->u.gather.my_rank * request->u.gather.packed_size;
+        iov.iov_len = request->u.gather.gather_bytes - gather_buf_offset;
+        iov.iov_base = (IOVBASE_TYPE *) (request->u.gather.gather_buf + gather_buf_offset);
+        opal_convertor_pack(&request->u.gather.send_converter, &iov, &iov_count, &max_data);
+
+        opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                            "%s:%d:rank(%d): root - gather_buf(%p) - gather_bytes(%lu)=packed_size(%ld) * size(%d)",
+                            __FILE__, __LINE__, request->u.gather.my_rank,
+                            request->u.gather.gather_buf, request->u.gather.gather_bytes,
+                            request->u.gather.packed_size, request->u.gather.size);
+    } else {
+        /* non-root nodes, allocate space to pack into and put from */
+        request->u.gather.gather_bytes=request->u.gather.packed_size;
+        request->u.gather.gather_buf = (char *) malloc(request->u.gather.gather_bytes);
+        if (NULL == request->u.gather.gather_buf) {
+            ret = OMPI_ERR_OUT_OF_RESOURCE; line = __LINE__; goto err_hdlr;
+        }
+        request->u.gather.free_after = 1;
+
+        iov.iov_len = request->u.gather.gather_bytes;
+        iov.iov_base = (IOVBASE_TYPE *) request->u.gather.gather_buf;
+        opal_convertor_pack(&request->u.gather.send_converter, &iov, &iov_count, &max_data);
+
+        opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                            "%s:%d:rank(%d): leaf - gather_buf(%p) - gather_bytes(%lu)=packed_size(%ld)",
+                            __FILE__, __LINE__, request->u.gather.my_rank,
+                            request->u.gather.gather_buf, request->u.gather.gather_bytes,
+                            request->u.gather.packed_size);
+    }
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    opal_output(ompi_coll_base_framework.framework_output,
+                "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+                __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+static int
+setup_gather_handles(struct ompi_communicator_t   *comm,
+                     ompi_coll_portals4_request_t *request,
+                     mca_coll_portals4_module_t   *portals4_module)
+{
+    int ret, line;
+
+    ptl_me_t  me;
+
+    /**********************************/
+    /* Setup Gather Handles           */
+    /**********************************/
+    COLL_PORTALS4_SET_BITS(request->u.gather.gather_match_bits, ompi_comm_get_cid(comm),
+            0, 0, COLL_PORTALS4_GATHER, 0, request->u.gather.coll_count);
+
+    ret = PtlCTAlloc(mca_coll_portals4_component.ni_h,
+                     &request->u.gather.gather_cth);
+    if (PTL_OK != ret) { ret = OMPI_ERR_TEMP_OUT_OF_RESOURCE; line = __LINE__; goto err_hdlr; }
+
+    request->u.gather.gather_mdh = mca_coll_portals4_component.data_md_h;
+    request->u.gather.gather_offset = (ptl_size_t)request->u.gather.gather_buf;
+
+    /* children put here */
+    me.start = request->u.gather.gather_buf;
+    me.length = request->u.gather.gather_bytes;
+    me.ct_handle = request->u.gather.gather_cth;
+    me.min_free = 0;
+    me.uid = mca_coll_portals4_component.uid;
+    me.options = PTL_ME_OP_PUT | PTL_ME_EVENT_SUCCESS_DISABLE |
+        PTL_ME_EVENT_LINK_DISABLE | PTL_ME_EVENT_UNLINK_DISABLE |
+        PTL_ME_EVENT_CT_COMM;
+    me.match_id.phys.nid = PTL_NID_ANY;
+    me.match_id.phys.pid = PTL_PID_ANY;
+    me.match_bits = request->u.gather.gather_match_bits;
+    me.ignore_bits = 0;
+    ret = PtlMEAppend(mca_coll_portals4_component.ni_h,
+                      mca_coll_portals4_component.pt_idx,
+                      &me,
+                      PTL_PRIORITY_LIST,
+                      NULL,
+                      &request->u.gather.gather_meh);
+    if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    opal_output(ompi_coll_base_framework.framework_output,
+                "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+                __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+static int
+setup_sync_handles(struct ompi_communicator_t   *comm,
+                   ompi_coll_portals4_request_t *request,
+                   mca_coll_portals4_module_t   *portals4_module)
+{
+    int ret, line;
+
+    ptl_me_t  me;
+
+    /**********************************/
+    /* Setup Sync Handles             */
+    /**********************************/
+    COLL_PORTALS4_SET_BITS(request->u.gather.sync_match_bits, ompi_comm_get_cid(comm),
+            0, 1, COLL_PORTALS4_GATHER, 0, request->u.gather.coll_count);
+
+    ret = PtlCTAlloc(mca_coll_portals4_component.ni_h,
+                     &request->u.gather.sync_cth);
+    if (PTL_OK != ret) { ret = OMPI_ERR_TEMP_OUT_OF_RESOURCE; line = __LINE__; goto err_hdlr; }
+
+    request->u.gather.sync_mdh = mca_coll_portals4_component.zero_md_h;
+
+    me.start = NULL;
+    me.length = 0;
+    me.ct_handle = request->u.gather.sync_cth;
+    me.min_free = 0;
+    me.uid = mca_coll_portals4_component.uid;
+    me.options = PTL_ME_OP_PUT | PTL_ME_EVENT_SUCCESS_DISABLE |
+        PTL_ME_EVENT_LINK_DISABLE | PTL_ME_EVENT_UNLINK_DISABLE |
+        PTL_ME_EVENT_CT_COMM | PTL_ME_EVENT_CT_OVERFLOW;
+    me.match_id.phys.nid = PTL_NID_ANY;
+    me.match_id.phys.pid = PTL_PID_ANY;
+    me.match_bits = request->u.gather.sync_match_bits;
+    me.ignore_bits = 0;
+    ret = PtlMEAppend(mca_coll_portals4_component.ni_h,
+                      mca_coll_portals4_component.pt_idx,
+                      &me,
+                      PTL_PRIORITY_LIST,
+                      NULL,
+                      &request->u.gather.sync_meh);
+    if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    opal_output(ompi_coll_base_framework.framework_output,
+                "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+                __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+static int
+cleanup_gather_handles(ompi_coll_portals4_request_t *request)
+{
+    int ret, line;
+
+    /**********************************/
+    /* Cleanup Gather Handles             */
+    /**********************************/
+    ret = PtlMEUnlink(request->u.gather.gather_meh);
+    if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+
+    ret = PtlCTFree(request->u.gather.gather_cth);
+    if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    opal_output(ompi_coll_base_framework.framework_output,
+                "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+                __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+static int
+cleanup_sync_handles(ompi_coll_portals4_request_t *request)
+{
+    int ret, line;
+
+    /**********************************/
+    /* Cleanup Sync Handles             */
+    /**********************************/
+    ret = PtlMEUnlink(request->u.gather.sync_meh);
+    if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+
+    ret = PtlCTFree(request->u.gather.sync_cth);
+    if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    opal_output(ompi_coll_base_framework.framework_output,
+                "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+                __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+static int
+ompi_coll_portals4_gather_intra_binomial_top(const void *sbuf, int scount, struct ompi_datatype_t *sdtype,
+                                             void *rbuf, int rcount, struct ompi_datatype_t *rdtype,
+                                             int root,
+                                             struct ompi_communicator_t *comm,
+                                             ompi_coll_portals4_request_t *request,
+                                             mca_coll_base_module_t *module)
+{
+    mca_coll_portals4_module_t *portals4_module = (mca_coll_portals4_module_t*) module;
+    int ret, line;
+    ptl_ct_event_t ct;
+
+    ptl_ct_event_t sync_incr_event;
+
+    int vrank=-1;
+
+    int32_t i=0;
+
+    ompi_coll_portals4_tree_t* bmtree;
+
+    int32_t expected_ops =0;
+    int32_t expected_acks=0;
+
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra_binomial_top enter rank %d", request->u.gather.my_rank));
+
+    request->type = OMPI_COLL_PORTALS4_TYPE_GATHER;
+    request->u.gather.gather_buf=NULL;
+    request->u.gather.gather_mdh=PTL_INVALID_HANDLE;
+    request->u.gather.gather_cth=PTL_INVALID_HANDLE;
+    request->u.gather.gather_meh=PTL_INVALID_HANDLE;
+    request->u.gather.sync_mdh=PTL_INVALID_HANDLE;
+    request->u.gather.sync_cth=PTL_INVALID_HANDLE;
+    request->u.gather.sync_meh=PTL_INVALID_HANDLE;
+
+    request->u.gather.my_rank   = ompi_comm_rank(comm);
+    request->u.gather.size      = ompi_comm_size(comm);
+    request->u.gather.root_rank = root;
+    request->u.gather.sbuf      = sbuf;
+    request->u.gather.rbuf      = rbuf;
+    if ((root == request->u.gather.my_rank) && (sbuf == MPI_IN_PLACE)) {
+        request->u.gather.pack_src_buf   = rbuf;
+        request->u.gather.pack_src_count = rcount;
+        request->u.gather.pack_src_dtype = rdtype;
+    } else {
+        request->u.gather.pack_src_buf    = sbuf;
+        request->u.gather.pack_src_count  = scount;
+        request->u.gather.pack_src_dtype  = sdtype;
+        request->u.gather.pack_src_offset = 0;
+    }
+    ompi_datatype_get_extent(request->u.gather.pack_src_dtype,
+                             &request->u.gather.pack_src_lb,
+                             &request->u.gather.pack_src_extent);
+    ompi_datatype_get_true_extent(request->u.gather.pack_src_dtype,
+                                  &request->u.gather.pack_src_true_lb,
+                                  &request->u.gather.pack_src_true_extent);
+    request->u.gather.unpack_dst_buf   = rbuf;
+    request->u.gather.unpack_dst_count = rcount;
+    request->u.gather.unpack_dst_dtype = rdtype;
+    ompi_datatype_get_extent(request->u.gather.unpack_dst_dtype,
+                             &request->u.gather.unpack_dst_lb,
+                             &request->u.gather.unpack_dst_extent);
+    ompi_datatype_get_true_extent(request->u.gather.unpack_dst_dtype,
+                                  &request->u.gather.unpack_dst_true_lb,
+                                  &request->u.gather.unpack_dst_true_extent);
+
+    if ((root == request->u.gather.my_rank) && (sbuf == MPI_IN_PLACE)) {
+        request->u.gather.pack_src_offset = request->u.gather.pack_src_extent * request->u.gather.pack_src_count * request->u.gather.my_rank;
+    }
+
+    opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                        "%s:%d:vrank(%d): request->u.gather.pack_src_offset(%lu)",
+                        __FILE__, __LINE__, vrank,
+                        request->u.gather.pack_src_offset);
+
+    /**********************************/
+    /* Setup Common Parameters        */
+    /**********************************/
+
+    request->u.gather.coll_count = opal_atomic_add_size_t(&portals4_module->coll_count, 1);
+
+    COLL_PORTALS4_UPDATE_IN_ORDER_BMTREE( comm, portals4_module, request->u.gather.root_rank );
+    bmtree = portals4_module->cached_in_order_bmtree;
+
+    vrank = VRANK(request->u.gather.my_rank, request->u.gather.root_rank, request->u.gather.size);
+
+    ret = setup_gather_buffers_binomial(comm, request, portals4_module);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    ret = setup_gather_handles(comm, request, portals4_module);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    ret = setup_sync_handles(comm, request, portals4_module);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    /***********************************************/
+    /* Chain the RTR and Recv-ACK to the Gather CT */
+    /***********************************************/
+    if (vrank != 0) {
+        sync_incr_event.success=1;
+        sync_incr_event.failure=0;
+        ret = PtlTriggeredCTInc(request->u.gather.gather_cth,
+                                sync_incr_event,
+                                request->u.gather.sync_cth,
+                                1);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+        ret = PtlTriggeredCTInc(request->u.gather.gather_cth,
+                                sync_incr_event,
+                                request->u.gather.sync_cth,
+                                2);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+    }
+
+    /**********************************/
+    /* do the gather                  */
+    /**********************************/
+    if (vrank == 0) {
+        /* root, so do nothing */
+
+        expected_ops=bmtree->tree_nextsize; /* gather put from each child */
+        expected_acks=0;
+
+    } else {
+        int32_t parent = bmtree->tree_prev;
+        int32_t vparent = VRANK(parent, request->u.gather.root_rank, request->u.gather.size);
+
+        ptl_size_t remote_offset=(vrank-vparent) * request->u.gather.packed_size;
+
+        opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                            "%s:%d:vrank(%d): remote_offset(%lu)=(vrank(%d)-vparent(%d)) * packed_size(%ld)",
+                            __FILE__, __LINE__, vrank,
+                            remote_offset, vrank, vparent, request->u.gather.packed_size);
+
+        expected_ops=bmtree->tree_nextsize + 1; /* gather put from each child + a chained RTR */
+        expected_acks=1;                        /* Recv-ACK from parent */
+
+        ret = PtlTriggeredPut(request->u.gather.gather_mdh,
+                              request->u.gather.gather_offset,
+                              request->u.gather.gather_bytes,
+                              PTL_NO_ACK_REQ,
+                              ompi_coll_portals4_get_peer(comm, parent),
+                              mca_coll_portals4_component.pt_idx,
+                              request->u.gather.gather_match_bits,
+                              remote_offset,
+                              NULL,
+                              0,
+                              request->u.gather.gather_cth,
+                              expected_ops);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+    }
+
+    /************************************/
+    /* put Recv-ACK to each child       */
+    /************************************/
+    for (i=0;i<bmtree->tree_nextsize;i++) {
+        int32_t child=bmtree->tree_next[i];
+        ret = PtlTriggeredPut(request->u.gather.sync_mdh,
+                              0,
+                              0,
+                              PTL_NO_ACK_REQ,
+                              ompi_coll_portals4_get_peer(comm, child),
+                              mca_coll_portals4_component.pt_idx,
+                              request->u.gather.sync_match_bits,
+                              0,
+                              NULL,
+                              0,
+                              request->u.gather.gather_cth,
+                              expected_ops);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+    }
+
+    expected_ops+=expected_acks;
+
+    if (!request->u.gather.is_sync) {
+        /******************************************/
+        /* put to finish pt when all ops complete */
+        /******************************************/
+        ret = PtlTriggeredPut(mca_coll_portals4_component.zero_md_h,
+                0,
+                0,
+                PTL_NO_ACK_REQ,
+                ompi_coll_portals4_get_peer(comm, request->u.gather.my_rank),
+                mca_coll_portals4_component.finish_pt_idx,
+                0,
+                0,
+                NULL,
+                (uintptr_t) request,
+                request->u.gather.gather_cth,
+                expected_ops);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+    }
+
+#ifdef RTR_USES_TRIGGERED_PUT
+    /**********************************/
+    /* put RTR to each child          */
+    /**********************************/
+    for (i=0;i<bmtree->tree_nextsize;i++) {
+        int32_t child=bmtree->tree_next[i];
+        ret = PtlTriggeredPut(request->u.gather.sync_mdh,
+                              0,
+                              0,
+                              PTL_NO_ACK_REQ,
+                              ompi_coll_portals4_get_peer(comm, child),
+                              mca_coll_portals4_component.pt_idx,
+                              request->u.gather.sync_match_bits,
+                              0,
+                              NULL,
+                              0,
+                              request->u.gather.sync_cth,
+                              0);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+    }
+#else
+    /**********************************/
+    /* put RTR to each child          */
+    /**********************************/
+    for (i=0;i<bmtree->tree_nextsize;i++) {
+        int32_t child=bmtree->tree_next[i];
+        ret = PtlPut(request->u.gather.sync_mdh,
+                     0,
+                     0,
+                     PTL_NO_ACK_REQ,
+                     ompi_coll_portals4_get_peer(comm, child),
+                     mca_coll_portals4_component.pt_idx,
+                     request->u.gather.sync_match_bits,
+                     0,
+                     NULL,
+                     0);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+    }
+#endif
+
+    if (request->u.gather.is_sync) {
+        opal_output_verbose(10, ompi_coll_base_framework.framework_output,
+                            "%s:%d:vrank(%d): calling CTWait(expected_ops=%d)\n",
+                            __FILE__, __LINE__, vrank, expected_ops);
+
+        /********************************/
+        /* Wait for all ops to complete */
+        /********************************/
+        ret = PtlCTWait(request->u.gather.gather_cth, expected_ops, &ct);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+
+        opal_output_verbose(10, ompi_coll_base_framework.framework_output,
+                            "%s:%d:vrank(%d): completed CTWait(expected_ops=%d)\n",
+                            __FILE__, __LINE__, vrank, expected_ops);
+    }
+
+    ompi_coll_portals4_destroy_tree(&(portals4_module->cached_in_order_bmtree));
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra_binomial_top exit rank %d", request->u.gather.my_rank));
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    if (NULL != request->u.gather.gather_buf)
+        free(request->u.gather.gather_buf);
+
+    ompi_coll_portals4_destroy_tree(&(portals4_module->cached_in_order_bmtree));
+
+    opal_output(ompi_coll_base_framework.framework_output,
+                "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+                __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+static int
+ompi_coll_portals4_gather_intra_linear_top(const void *sbuf, int scount, struct ompi_datatype_t *sdtype,
+                                           void *rbuf, int rcount, struct ompi_datatype_t *rdtype,
+                                           int root,
+                                           struct ompi_communicator_t *comm,
+                                           ompi_coll_portals4_request_t *request,
+                                           mca_coll_base_module_t *module)
+{
+    mca_coll_portals4_module_t *portals4_module = (mca_coll_portals4_module_t*) module;
+    int ret, line;
+    ptl_ct_event_t ct;
+
+    ptl_ct_event_t sync_incr_event;
+
+    int8_t i_am_root;
+
+    int32_t i=0;
+
+    int32_t expected_ops =0;
+    int32_t expected_acks=0;
+
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra_linear_top enter rank %d", request->u.gather.my_rank));
+
+    request->type = OMPI_COLL_PORTALS4_TYPE_GATHER;
+    request->u.gather.gather_buf=NULL;
+    request->u.gather.gather_mdh=PTL_INVALID_HANDLE;
+    request->u.gather.gather_cth=PTL_INVALID_HANDLE;
+    request->u.gather.gather_meh=PTL_INVALID_HANDLE;
+    request->u.gather.sync_mdh=PTL_INVALID_HANDLE;
+    request->u.gather.sync_cth=PTL_INVALID_HANDLE;
+    request->u.gather.sync_meh=PTL_INVALID_HANDLE;
+
+    request->u.gather.my_rank   = ompi_comm_rank(comm);
+    request->u.gather.size      = ompi_comm_size(comm);
+    request->u.gather.root_rank = root;
+    request->u.gather.sbuf      = sbuf;
+    request->u.gather.rbuf      = rbuf;
+    if ((root == request->u.gather.my_rank) && (sbuf == MPI_IN_PLACE)) {
+        request->u.gather.pack_src_buf   = rbuf;
+        request->u.gather.pack_src_count = rcount;
+        request->u.gather.pack_src_dtype = rdtype;
+    } else {
+        request->u.gather.pack_src_buf    = sbuf;
+        request->u.gather.pack_src_count  = scount;
+        request->u.gather.pack_src_dtype  = sdtype;
+        request->u.gather.pack_src_offset = 0;
+    }
+    ompi_datatype_get_extent(request->u.gather.pack_src_dtype,
+                             &request->u.gather.pack_src_lb,
+                             &request->u.gather.pack_src_extent);
+    ompi_datatype_get_true_extent(request->u.gather.pack_src_dtype,
+                                  &request->u.gather.pack_src_true_lb,
+                                  &request->u.gather.pack_src_true_extent);
+    request->u.gather.unpack_dst_buf   = rbuf;
+    request->u.gather.unpack_dst_count = rcount;
+    request->u.gather.unpack_dst_dtype = rdtype;
+    ompi_datatype_get_extent(request->u.gather.unpack_dst_dtype,
+                             &request->u.gather.unpack_dst_lb,
+                             &request->u.gather.unpack_dst_extent);
+    ompi_datatype_get_true_extent(request->u.gather.unpack_dst_dtype,
+                                  &request->u.gather.unpack_dst_true_lb,
+                                  &request->u.gather.unpack_dst_true_extent);
+
+    if ((root == request->u.gather.my_rank) && (sbuf == MPI_IN_PLACE)) {
+        request->u.gather.pack_src_offset = request->u.gather.pack_src_extent * request->u.gather.pack_src_count * request->u.gather.my_rank;
+    }
+
+    opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                        "%s:%d:rank(%d): request->u.gather.pack_src_offset(%lu)",
+                        __FILE__, __LINE__, request->u.gather.my_rank,
+                        request->u.gather.pack_src_offset);
+
+    /**********************************/
+    /* Setup Common Parameters        */
+    /**********************************/
+
+    i_am_root = (request->u.gather.my_rank == request->u.gather.root_rank);
+
+    request->u.gather.coll_count = opal_atomic_add_size_t(&portals4_module->coll_count, 1);
+
+    ret = setup_gather_buffers_linear(comm, request, portals4_module);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    ret = setup_gather_handles(comm, request, portals4_module);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    ret = setup_sync_handles(comm, request, portals4_module);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    /***********************************************/
+    /* Chain the RTR and Recv-ACK to the Gather CT */
+    /***********************************************/
+    if (!i_am_root) {
+        sync_incr_event.success=1;
+        sync_incr_event.failure=0;
+        ret = PtlTriggeredCTInc(request->u.gather.gather_cth,
+                                sync_incr_event,
+                                request->u.gather.sync_cth,
+                                1);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+        ret = PtlTriggeredCTInc(request->u.gather.gather_cth,
+                                sync_incr_event,
+                                request->u.gather.sync_cth,
+                                2);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+    }
+
+    /**********************************/
+    /* do the gather                  */
+    /**********************************/
+    if (i_am_root) {
+        /* root, so do nothing */
+
+        expected_ops=request->u.gather.size-1; /* gather put from all other ranks */
+        expected_acks=0;
+
+    } else {
+        ptl_size_t remote_offset=request->u.gather.my_rank * request->u.gather.packed_size;
+
+        opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                            "%s:%d:rank(%d): remote_offset(%lu)=rank(%d) * packed_size(%ld)",
+                            __FILE__, __LINE__, request->u.gather.my_rank,
+                            remote_offset, request->u.gather.my_rank, request->u.gather.packed_size);
+
+        expected_ops=1;  /* chained RTR */
+        expected_acks=1; /* Recv-ACK from root */
+
+        ret = PtlTriggeredPut(request->u.gather.gather_mdh,
+                              request->u.gather.gather_offset,
+                              request->u.gather.gather_bytes,
+                              PTL_NO_ACK_REQ,
+                              ompi_coll_portals4_get_peer(comm, request->u.gather.root_rank),
+                              mca_coll_portals4_component.pt_idx,
+                              request->u.gather.gather_match_bits,
+                              remote_offset,
+                              NULL,
+                              0,
+                              request->u.gather.gather_cth,
+                              expected_ops);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+    }
+
+    /*****************************************/
+    /* root puts Recv-ACK to all other ranks */
+    /*****************************************/
+    if (i_am_root) {
+        for (i=0;i<request->u.gather.size;i++) {
+            if (i == request->u.gather.root_rank) { continue; }
+            ret = PtlTriggeredPut(request->u.gather.sync_mdh,
+                                  0,
+                                  0,
+                                  PTL_NO_ACK_REQ,
+                                  ompi_coll_portals4_get_peer(comm, i),
+                                  mca_coll_portals4_component.pt_idx,
+                                  request->u.gather.sync_match_bits,
+                                  0,
+                                  NULL,
+                                  0,
+                                  request->u.gather.gather_cth,
+                                  expected_ops);
+            if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+        }
+    }
+
+    expected_ops+=expected_acks;
+
+    if (!request->u.gather.is_sync) {
+        /******************************************/
+        /* put to finish pt when all ops complete */
+        /******************************************/
+        ret = PtlTriggeredPut(mca_coll_portals4_component.zero_md_h,
+                0,
+                0,
+                PTL_NO_ACK_REQ,
+                ompi_coll_portals4_get_peer(comm, request->u.gather.my_rank),
+                mca_coll_portals4_component.finish_pt_idx,
+                0,
+                0,
+                NULL,
+                (uintptr_t) request,
+                request->u.gather.gather_cth,
+                expected_ops);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+    }
+
+#ifdef RTR_USES_TRIGGERED_PUT
+    /************************************/
+    /* root puts RTR to all other ranks */
+    /************************************/
+    if (i_am_root) {
+        for (i=0;i<request->u.gather.size;i++) {
+            if (i == request->u.gather.root_rank) { continue; }
+            ret = PtlTriggeredPut(request->u.gather.sync_mdh,
+                                  0,
+                                  0,
+                                  PTL_NO_ACK_REQ,
+                                  ompi_coll_portals4_get_peer(comm, i),
+                                  mca_coll_portals4_component.pt_idx,
+                                  request->u.gather.sync_match_bits,
+                                  0,
+                                  NULL,
+                                  0,
+                                  request->u.gather.sync_cth,
+                                  0);
+            if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+        }
+    }
+#else
+    /************************************/
+    /* root puts RTR to all other ranks */
+    /************************************/
+    if (i_am_root) {
+        for (i=0;i<request->u.gather.size;i++) {
+            if (i == request->u.gather.root_rank) { continue; }
+            ret = PtlPut(request->u.gather.sync_mdh,
+                         0,
+                         0,
+                         PTL_NO_ACK_REQ,
+                         ompi_coll_portals4_get_peer(comm, i),
+                         mca_coll_portals4_component.pt_idx,
+                         request->u.gather.sync_match_bits,
+                         0,
+                         NULL,
+                         0);
+            if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+        }
+    }
+#endif
+
+    if (request->u.gather.is_sync) {
+        opal_output_verbose(10, ompi_coll_base_framework.framework_output,
+                "calling CTWait(expected_ops=%d)\n", expected_ops);
+
+        /********************************/
+        /* Wait for all ops to complete */
+        /********************************/
+        ret = PtlCTWait(request->u.gather.gather_cth, expected_ops, &ct);
+        if (PTL_OK != ret) { ret = OMPI_ERROR; line = __LINE__; goto err_hdlr; }
+
+        opal_output_verbose(10, ompi_coll_base_framework.framework_output,
+                "completed CTWait(expected_ops=%d)\n", expected_ops);
+    }
+
+    ompi_coll_portals4_destroy_tree(&(portals4_module->cached_in_order_bmtree));
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra_linear_top exit rank %d", request->u.gather.my_rank));
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    if (NULL != request->u.gather.gather_buf)
+        free(request->u.gather.gather_buf);
+
+    ompi_coll_portals4_destroy_tree(&(portals4_module->cached_in_order_bmtree));
+
+    opal_output(ompi_coll_base_framework.framework_output,
+                "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+                __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+static int
+ompi_coll_portals4_gather_intra_binomial_bottom(struct ompi_communicator_t *comm,
+                                                ompi_coll_portals4_request_t *request)
+{
+    int ret, line;
+    int i;
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra_binomial_bottom enter rank %d", request->u.gather.my_rank));
+
+    ret = cleanup_gather_handles(request);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    ret = cleanup_sync_handles(request);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    if (request->u.gather.my_rank == request->u.gather.root_rank) {
+        uint32_t iov_count = 1;
+        struct iovec iov;
+        size_t max_data;
+
+        for (i=0;i<request->u.gather.size;i++) {
+            uint64_t offset = request->u.gather.unpack_dst_extent * request->u.gather.unpack_dst_count * ((request->u.gather.my_rank + i) % request->u.gather.size);
+
+            opal_output_verbose(30, ompi_coll_base_framework.framework_output,
+                                "%s:%d:rank(%d): offset(%lu)",
+                                __FILE__, __LINE__, request->u.gather.my_rank,
+                                offset);
+
+            ompi_coll_portals4_create_recv_converter (&request->u.gather.recv_converter,
+                                                      request->u.gather.unpack_dst_buf + offset,
+                                                      ompi_comm_peer_lookup(comm, request->u.gather.my_rank),
+                                                      request->u.gather.unpack_dst_count,
+                                                      request->u.gather.unpack_dst_dtype);
+
+            iov.iov_len = request->u.gather.packed_size;
+            iov.iov_base = (IOVBASE_TYPE *) ((char *)request->u.gather.gather_buf + (request->u.gather.packed_size*i));
+            opal_convertor_unpack(&request->u.gather.recv_converter, &iov, &iov_count, &max_data);
+
+            OBJ_DESTRUCT(&request->u.gather.recv_converter);
+        }
+    }
+
+    if (request->u.gather.free_after)
+        free(request->u.gather.gather_buf);
+
+    request->super.req_status.MPI_ERROR = OMPI_SUCCESS;
+
+    OPAL_THREAD_LOCK(&ompi_request_lock);
+    ompi_request_complete(&request->super, true);
+    OPAL_THREAD_UNLOCK(&ompi_request_lock);
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra_binomial_bottom exit rank %d", request->u.gather.my_rank));
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    request->super.req_status.MPI_ERROR = ret;
+
+    if (request->u.gather.free_after)
+        free(request->u.gather.gather_buf);
+
+    opal_output(ompi_coll_base_framework.framework_output,
+            "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+            __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+static int
+ompi_coll_portals4_gather_intra_linear_bottom(struct ompi_communicator_t *comm,
+                                              ompi_coll_portals4_request_t *request)
+{
+    int ret, line;
+    int i;
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra_linear_bottom enter rank %d", request->u.gather.my_rank));
+
+    ret = cleanup_gather_handles(request);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    ret = cleanup_sync_handles(request);
+    if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+    if (request->u.gather.my_rank == request->u.gather.root_rank) {
+        uint32_t iov_count = 1;
+        struct iovec iov;
+        size_t max_data;
+
+        for (i=0;i<request->u.gather.size;i++) {
+            ompi_coll_portals4_create_recv_converter (&request->u.gather.recv_converter,
+                                                      request->u.gather.unpack_dst_buf + (request->u.gather.unpack_dst_extent*request->u.gather.unpack_dst_count*i),
+                                                      ompi_comm_peer_lookup(comm, request->u.gather.my_rank),
+                                                      request->u.gather.unpack_dst_count,
+                                                      request->u.gather.unpack_dst_dtype);
+
+            iov.iov_len = request->u.gather.packed_size;
+            iov.iov_base = (IOVBASE_TYPE *) ((char *)request->u.gather.gather_buf + (request->u.gather.packed_size*i));
+            opal_convertor_unpack(&request->u.gather.recv_converter, &iov, &iov_count, &max_data);
+
+            OBJ_DESTRUCT(&request->u.gather.recv_converter);
+        }
+    }
+
+    if (request->u.gather.free_after)
+        free(request->u.gather.gather_buf);
+
+    request->super.req_status.MPI_ERROR = OMPI_SUCCESS;
+
+    OPAL_THREAD_LOCK(&ompi_request_lock);
+    ompi_request_complete(&request->super, true);
+    OPAL_THREAD_UNLOCK(&ompi_request_lock);
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra_linear_bottom exit rank %d", request->u.gather.my_rank));
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    request->super.req_status.MPI_ERROR = ret;
+
+    if (request->u.gather.free_after)
+        free(request->u.gather.gather_buf);
+
+    opal_output(ompi_coll_base_framework.framework_output,
+            "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+            __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+int
+ompi_coll_portals4_gather_intra(const void *sbuf, int scount, struct ompi_datatype_t *sdtype,
+                                void *rbuf, int rcount, struct ompi_datatype_t *rdtype,
+                                int root,
+                                struct ompi_communicator_t *comm,
+                                mca_coll_base_module_t *module)
+{
+    int ret, line;
+
+    ompi_coll_portals4_request_t *request;
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra enter rank %d", ompi_comm_rank(comm)));
+
+    /*
+     *  allocate a portals4 request
+     */
+    OMPI_COLL_PORTALS4_REQUEST_ALLOC(comm, request);
+    if (NULL == request) {
+        ret = OMPI_ERR_TEMP_OUT_OF_RESOURCE; line = __LINE__; goto err_hdlr;
+    }
+    request->u.gather.is_sync = 1;
+
+    /*
+     *  initiate the gather
+     *
+     *  this request is marked synchronous (is_sync==1), so PtlCTWait()
+     *  will be called to wait for completion.
+     */
+    if (1 == mca_coll_portals4_component.use_binomial_gather_algorithm) {
+        ret = ompi_coll_portals4_gather_intra_binomial_top(sbuf, scount, sdtype,
+                                                           rbuf, rcount, rdtype,
+                                                           root,
+                                                           comm,
+                                                           request,
+                                                           module);
+        if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+        ret = ompi_coll_portals4_gather_intra_binomial_bottom(comm, request);
+        if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+    } else {
+        ret = ompi_coll_portals4_gather_intra_linear_top(sbuf, scount, sdtype,
+                                                         rbuf, rcount, rdtype,
+                                                         root,
+                                                         comm,
+                                                         request,
+                                                         module);
+        if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+
+        ret = ompi_coll_portals4_gather_intra_linear_bottom(comm, request);
+        if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+    }
+
+    /*
+     *  return the portals4 request
+     */
+    OMPI_COLL_PORTALS4_REQUEST_RETURN(request);
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:gather_intra exit rank %d", request->u.gather.my_rank));
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    opal_output(ompi_coll_base_framework.framework_output,
+            "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+            __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+
+int
+ompi_coll_portals4_igather_intra(const void *sbuf, int scount, struct ompi_datatype_t *sdtype,
+                                 void *rbuf, int rcount, struct ompi_datatype_t *rdtype,
+                                 int root,
+                                 struct ompi_communicator_t *comm,
+                                 ompi_request_t **ompi_request,
+                                 mca_coll_base_module_t *module)
+{
+    int ret, line;
+
+    ompi_coll_portals4_request_t *request;
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:igather_intra enter rank %d", ompi_comm_rank(comm)));
+
+    /*
+     *  allocate a portals4 request
+     */
+    OMPI_COLL_PORTALS4_REQUEST_ALLOC(comm, request);
+    if (NULL == request) {
+        ret = OMPI_ERR_TEMP_OUT_OF_RESOURCE; line = __LINE__; goto err_hdlr;
+    }
+    *ompi_request = &request->super;
+    request->u.gather.is_sync = 0;
+
+    /*
+     *  initiate the gather
+     *
+     *  this request is marked asynchronous (is_sync==0), so
+     *  portals4_progress() will handle completion.
+     */
+    if (1 == mca_coll_portals4_component.use_binomial_gather_algorithm) {
+        ret = ompi_coll_portals4_gather_intra_binomial_top(sbuf, scount, sdtype,
+                                                           rbuf, rcount, rdtype,
+                                                           root,
+                                                           comm,
+                                                           request,
+                                                           module);
+        if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+    } else {
+        ret = ompi_coll_portals4_gather_intra_linear_top(sbuf, scount, sdtype,
+                                                         rbuf, rcount, rdtype,
+                                                         root,
+                                                         comm,
+                                                         request,
+                                                         module);
+        if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+    }
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:igather_intra exit rank %d", request->u.gather.my_rank));
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    opal_output(ompi_coll_base_framework.framework_output,
+            "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+            __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
+
+
+int
+ompi_coll_portals4_igather_intra_fini(ompi_coll_portals4_request_t *request)
+{
+    int ret, line;
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:igather_intra_fini enter rank %d", request->u.gather.my_rank));
+
+    /*
+     *  cleanup the gather
+     */
+    if (1 == mca_coll_portals4_component.use_binomial_gather_algorithm) {
+        ret = ompi_coll_portals4_gather_intra_binomial_bottom(request->super.req_mpi_object.comm, request);
+        if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+    } else {
+        ret = ompi_coll_portals4_gather_intra_linear_bottom(request->super.req_mpi_object.comm, request);
+        if (MPI_SUCCESS != ret) { line = __LINE__; goto err_hdlr; }
+    }
+
+    OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
+                 "coll:portals4:igather_intra_fini exit rank %d", request->u.gather.my_rank));
+
+    return OMPI_SUCCESS;
+
+err_hdlr:
+    opal_output(ompi_coll_base_framework.framework_output,
+            "%s:%4d:%4d\tError occurred ret=%d, rank %2d",
+            __FILE__, __LINE__, line, ret, request->u.gather.my_rank);
+
+    return ret;
+}
diff --git a/ompi/mca/coll/portals4/coll_portals4_request.h b/ompi/mca/coll/portals4/coll_portals4_request.h
index 175835381e..341e6b6ae7 100644
--- a/ompi/mca/coll/portals4/coll_portals4_request.h
+++ b/ompi/mca/coll/portals4/coll_portals4_request.h
@@ -83,6 +83,46 @@ struct ompi_coll_portals4_request_t {
             ptl_handle_ct_t ack_ct_h;
         } allreduce;
 
+        struct {
+            opal_convertor_t        send_converter;
+            opal_convertor_t        recv_converter;
+            size_t                  packed_size;
+    	    int8_t                  is_sync;
+            int8_t                  free_after;
+            size_t                  coll_count;
+    	    char                   *gather_buf;
+    	    uint64_t                gather_bytes;
+            ptl_match_bits_t        gather_match_bits;
+            ptl_handle_md_t         gather_mdh;
+            ptl_size_t              gather_offset;
+            ptl_handle_ct_t         gather_cth;
+            ptl_handle_md_t         gather_meh;
+            ptl_match_bits_t        sync_match_bits;
+            ptl_handle_md_t         sync_mdh;
+            ptl_handle_ct_t         sync_cth;
+            ptl_handle_me_t         sync_meh;
+            int                     my_rank;
+            int                     root_rank;
+            int                     size;
+            const void             *sbuf;
+            void                   *rbuf;
+            const char             *pack_src_buf;
+            int                     pack_src_count;
+            struct ompi_datatype_t *pack_src_dtype;
+            MPI_Aint                pack_src_extent;
+            MPI_Aint                pack_src_true_extent;
+            MPI_Aint                pack_src_lb;
+            MPI_Aint                pack_src_true_lb;
+            MPI_Aint                pack_src_offset;
+            uint64_t                unpack_bytes;
+            char                   *unpack_dst_buf;
+            int                     unpack_dst_count;
+            struct ompi_datatype_t *unpack_dst_dtype;
+            MPI_Aint                unpack_dst_extent;
+            MPI_Aint                unpack_dst_true_extent;
+            MPI_Aint                unpack_dst_lb;
+            MPI_Aint                unpack_dst_true_lb;
+        } gather;
     } u;
 };
 typedef struct ompi_coll_portals4_request_t ompi_coll_portals4_request_t;