Add support for faster small messages. While sending a message, we check if

the data was buffered by the MX library. If it's the case then we declare
the send as completed and disable the completion event for the mx request.

This commit was SVN r12935.

config/ompi_check_mx.m4

@@ -41,6 +41,26 @@ AC_DEFUN([_OMPI_CHECK_MX_UNEXP_HANDLER],[
     unset mx_provide_unexp_handler
 ])
 
+AC_DEFUN([_OMPI_CHECK_MX_FORGET],[
+    #
+    # Check if the MX library provide the mx_forget function.
+    #
+    AC_MSG_CHECKING([for a MX version with mx_forget])
+    AC_TRY_LINK([#include <mx_extensions.h>],
+             [mx_forget(0, 0);],
+             [mx_provide_forget="yes"],
+             [mx_provide_forget="no"])
+    AC_MSG_RESULT([$mx_provide_forget])
+    AS_IF([test x"$mx_provide_forget" = "xyes"],
+          [mx_provide_forget=1
+           $2],
+          [mx_provide_forget=0
+           $3])
+    AC_DEFINE_UNQUOTED([MX_HAVE_FORGET], [$mx_provide_forget],
+                       [MX allow to forget the completion event for mx_requests])
+    unset mx_provide_forget
+])
+
 AC_DEFUN([_OMPI_CHECK_MX_CONFIG],[
     #
     # See if we have MX_API. OpenMPI require a MX version bigger than
@@ -110,6 +130,9 @@ AC_DEFUN([OMPI_CHECK_MX],[
                                  [ompi_check_mx_happy="no"])])
     AS_IF([test "$ompi_check_mx_happy" = "yes"],
           [_OMPI_CHECK_MX_UNEXP_HANDLER($1, [ompi_check_mx_register="yes"],
+                                        [ompi_check_mx_register="no"])])
+    AS_IF([test "$ompi_check_mx_happy" = "yes"],
+          [_OMPI_CHECK_MX_FORGET($1, [ompi_check_mx_register="yes"],
                                  [ompi_check_mx_register="no"])])
 
     CPPFLAGS="$ompi_check_mx_$1_save_CPPFLAGS"

ompi/mca/btl/mx/btl_mx.c

@@ -26,6 +26,8 @@
 #include "ompi/datatype/convertor.h" 
 #include "opal/prefetch.h"
 
+#include "mx_extensions.h"
+
 /**
  *
  */
@@ -247,12 +249,7 @@ mca_btl_mx_prepare_src( struct mca_btl_base_module_t* btl,
             if( OPAL_UNLIKELY(NULL == frag) ) {
                 return NULL;
             }
-#if 1
             frag->base.des_src_cnt = 2;
-#else
-            frag->base.des_src_cnt = 1;
-            iov.iov_base = (void*)((unsigned char*)frag->segment[0].seg_addr.pval + reserve);
-#endif
         }
     } else {
         MCA_BTL_MX_FRAG_ALLOC_EAGER( mx_btl, frag, rc );
@@ -262,17 +259,17 @@ mca_btl_mx_prepare_src( struct mca_btl_base_module_t* btl,
         frag->base.des_src_cnt = 1;
         iov.iov_base = (void*)((unsigned char*)frag->segment[0].seg_addr.pval + reserve);
     }
-    frag->segment[0].seg_len = reserve;
 
     iov.iov_len = max_data;
     (void)ompi_convertor_pack(convertor, &iov, &iov_count, &max_data );
     *size = max_data;
 
     if( 1 == frag->base.des_src_cnt ) {
-        frag->segment[0].seg_len += max_data;
+        frag->segment[0].seg_len = reserve + max_data;
         if( 0 == reserve )
             frag->segment[0].seg_addr.pval = iov.iov_base;
     } else {
+        frag->segment[0].seg_len       = reserve;
         frag->segment[1].seg_len       = max_data;
         frag->segment[1].seg_addr.pval = iov.iov_base;
     }
@@ -308,7 +305,7 @@ mca_btl_base_descriptor_t* mca_btl_mx_prepare_dst( struct mca_btl_base_module_t*
     int rc;
 
     MCA_BTL_MX_FRAG_ALLOC_USER(btl, frag, rc);
-    if(NULL == frag) {
+    if( OPAL_UNLIKELY(NULL == frag) ) {
         return NULL;
     }
 
@@ -320,7 +317,7 @@ mca_btl_base_descriptor_t* mca_btl_mx_prepare_dst( struct mca_btl_base_module_t*
     mx_segment.segment_length = frag->segment[0].seg_len;
     mx_return = mx_irecv( mx_btl->mx_endpoint, &mx_segment, 1, frag->segment[0].seg_key.key64, 
                           BTL_MX_PUT_MASK, NULL, &(frag->mx_request) );
-    if( MX_SUCCESS != mx_return ) {
+    if( OPAL_UNLIKELY(MX_SUCCESS != mx_return) ) {
         opal_output( 0, "Fail to re-register a fragment with the MX NIC ...\n" );
         MCA_BTL_MX_FRAG_RETURN( btl, frag );
         return NULL;
@@ -352,7 +349,7 @@ static int mca_btl_mx_put( struct mca_btl_base_module_t* btl,
     mx_segment_t mx_segment[2];
     mx_return_t mx_return;
 
-    if( MCA_BTL_MX_CONNECTED != ((mca_btl_mx_endpoint_t*)endpoint)->status ) {
+    if( OPAL_UNLIKELY(MCA_BTL_MX_CONNECTED != ((mca_btl_mx_endpoint_t*)endpoint)->status) ) {
         if( MCA_BTL_MX_NOT_REACHEABLE == ((mca_btl_mx_endpoint_t*)endpoint)->status )
             return OMPI_ERROR;
         if( MCA_BTL_MX_CONNECTION_PENDING == ((mca_btl_mx_endpoint_t*)endpoint)->status )
@@ -374,7 +371,7 @@ static int mca_btl_mx_put( struct mca_btl_base_module_t* btl,
     mx_return = mx_isend( mx_btl->mx_endpoint, mx_segment, descriptor->des_src_cnt,
                           endpoint->mx_peer_addr,
                           descriptor->des_dst[0].seg_key.key64, frag, &frag->mx_request );
-    if( MX_SUCCESS != mx_return ) {
+    if( OPAL_UNLIKELY(MX_SUCCESS != mx_return) ) {
         opal_output( 0, "mx_isend fails with error %s\n", mx_strerror(mx_return) );
         return OMPI_ERROR;
     }
@@ -403,7 +400,7 @@ int mca_btl_mx_send( struct mca_btl_base_module_t* btl,
     mx_return_t mx_return;
     uint64_t total_length;
 
-    if( MCA_BTL_MX_CONNECTED != ((mca_btl_mx_endpoint_t*)endpoint)->status ) {
+    if( OPAL_UNLIKELY(MCA_BTL_MX_CONNECTED != ((mca_btl_mx_endpoint_t*)endpoint)->status) ) {
         if( MCA_BTL_MX_NOT_REACHEABLE == ((mca_btl_mx_endpoint_t*)endpoint)->status )
             return OMPI_ERROR;
         if( MCA_BTL_MX_CONNECTION_PENDING == ((mca_btl_mx_endpoint_t*)endpoint)->status )
@@ -429,18 +426,41 @@ int mca_btl_mx_send( struct mca_btl_base_module_t* btl,
         opal_output( 0, "mx_isend fails with error %s\n", mx_strerror(mx_return) );
         return OMPI_ERROR;
     }
+
+#if MX_HAVE_FORGET
+    {
+        uint32_t mx_result;
+        mx_return = mx_ibuffered( mx_btl->mx_endpoint, &(frag->mx_request), &mx_result );
+        if( OPAL_UNLIKELY(MX_SUCCESS != mx_return) ) {
+            opal_output( 0, "mx_ibuffered failed with error %d (%s)\n",
+                         mx_return, mx_strerror(mx_return) );
+            return OMPI_ERROR;
+        }
+        if( mx_result ) {
+            mx_return = mx_forget( mx_btl->mx_endpoint, &(frag->mx_request) );
+            frag->base.des_cbfunc( &(mx_btl->super), frag->endpoint, &(frag->base), OMPI_SUCCESS);
+            if( OPAL_UNLIKELY(MX_SUCCESS != mx_return) ) {
+                opal_output( 0, "mx_forget failed with error %d (%s)\n",
+                             mx_return, mx_strerror(mx_return) );
+                return OMPI_ERROR;
+            }
+            return OMPI_SUCCESS;
+        }
+    }
+#endif
     if( 4096 > total_length ) {
         mx_status_t mx_status;
         uint32_t mx_result;
 
         /* let's check for completness */
         mx_return = mx_test( mx_btl->mx_endpoint, &(frag->mx_request), &mx_status, &mx_result );
-        if( MX_SUCCESS != mx_return ) 
+        if( OPAL_UNLIKELY(MX_SUCCESS != mx_return) ) 
             return OMPI_SUCCESS;
         /* call the completion callback */
         if( mx_result )
             frag->base.des_cbfunc( &(mx_btl->super), frag->endpoint, &(frag->base), OMPI_SUCCESS);
     }
+
     return OMPI_SUCCESS;
 }