btl/ugni: fix very poor aries bw problem

The handling of RDMA get alignment in ugni BTL for Aries
(cray xc) was wrong, resulting in very poor bandwidth
for ugni BTL on aries.

Verified using osu_bw now gives sensible bandwidth on
Aries.

Fixes #1005

Signed-off-by: Howard Pritchard <howardp@lanl.gov>

opal/mca/btl/ugni/btl_ugni_component.c

@@ -231,6 +231,9 @@ btl_ugni_component_register(void)
     /* determine if there are get alignment restrictions */
     GNI_GetDeviceType (&device_type);
 
+    /*
+     * see def. of ALIGNMENT_MASK to figure this one out
+     */
     if (GNI_DEVICE_GEMINI == device_type) {
         mca_btl_ugni_module.super.btl_get_alignment = 4;
     } else {

opal/mca/btl/ugni/btl_ugni_get.c

@@ -13,6 +13,12 @@
 #include "btl_ugni_rdma.h"
 #include "btl_ugni_smsg.h"
 
+/* 
+ * taken from osc_rdma_comm.h, ugh.
+ */
+
+#define ALIGNMENT_MASK(x) ((x) ? (x) - 1 : 0)
+
 int mca_btl_ugni_get (mca_btl_base_module_t *btl, struct mca_btl_base_endpoint_t *endpoint, void *local_address,
                       uint64_t remote_address, mca_btl_base_registration_handle_t *local_handle,
                       mca_btl_base_registration_handle_t *remote_handle, size_t size, int flags,
@@ -21,7 +27,8 @@ int mca_btl_ugni_get (mca_btl_base_module_t *btl, struct mca_btl_base_endpoint_t
     bool check;
 
     /* Check if the get is aligned/sized on a multiple of 4 */
-    check = !!((remote_address | (uint64_t)(intptr_t) local_address | size) & (mca_btl_ugni_module.super.btl_get_alignment - 1));
+    check = !!((remote_address | (uint64_t)(intptr_t) local_address | size) &
+                 ALIGNMENT_MASK(mca_btl_ugni_module.super.btl_get_alignment));
 
     if (OPAL_UNLIKELY(check || size > mca_btl_ugni_module.super.btl_get_limit)) {
         BTL_VERBOSE(("RDMA/FMA Get not available due to size or alignment restrictions"));