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Signed-off-by: Howard Pritchard <[email protected]>

Author: hppritcha

ompi/mca/coll/base/coll_base_bcast.c

@@ -35,6 +35,15 @@
 #include "coll_base_topo.h"
 #include "coll_base_util.h"
 
+/*
+ * if a > b return a- b otherwise 0
+ */
+static inline size_t
+rectify_diff(size_t a, size_t b)
+{
+    return a > b ? a - b : 0;
+}
+
 int
 ompi_coll_base_bcast_intra_generic( void* buffer,
                                      size_t original_count,
@@ -812,8 +821,11 @@ int ompi_coll_base_bcast_intra_scatter_allgather(
         if (vrank & mask) {
             int parent = (rank - mask + comm_size) % comm_size;
             /* Compute an upper bound on recv block size */
+            recv_count = rectify_diff(count, (size_t)(vrank * scatter_count));
+#if 0
             recv_count = (count > vrank * scatter_count) ? (count - vrank * scatter_count) : 0;
-            if (recv_count <= 0) {
+#endif
+            if (recv_count == 0) {
                 curr_count = 0;
             } else {
                 /* Recv data from parent */
@@ -833,7 +845,10 @@ int ompi_coll_base_bcast_intra_scatter_allgather(
     mask >>= 1;
     while (mask > 0) {
         if (vrank + mask < comm_size) {
+            send_count = rectify_diff(curr_count, (size_t)(scatter_count * mask));
+#if 0
             send_count = (curr_count > scatter_count * mask) ? curr_count - scatter_count * mask : 0;
+#endif
             if (send_count > 0) {
                 int child = (rank + mask) % comm_size;
                 err = MCA_PML_CALL(send((char *)buf + (ptrdiff_t)scatter_count * (vrank + mask) * extent,
@@ -865,8 +880,11 @@ int ompi_coll_base_bcast_intra_scatter_allgather(
         if (vremote < comm_size) {
             ptrdiff_t send_offset = vrank_tree_root * scatter_count * extent;
             ptrdiff_t recv_offset = vremote_tree_root * scatter_count * extent;
+            recv_count = rectify_diff(count, (size_t)(vremote_tree_root * scatter_count));
+#if 0
             recv_count = (count > vremote_tree_root * scatter_count) ?
                             (count - vremote_tree_root * scatter_count) : 0;
+#endif
             err = ompi_coll_base_sendrecv((char *)buf + send_offset,
                                           curr_count, datatype, remote,
                                           MCA_COLL_BASE_TAG_BCAST,
@@ -986,7 +1004,10 @@ int ompi_coll_base_bcast_intra_scatter_allgather_ring(
         if (vrank & mask) {
             int parent = (rank - mask + comm_size) % comm_size;
             /* Compute an upper bound on recv block size */
+            recv_count = rectify_diff(count, (size_t)(vrank * scatter_count));
+#if 0
             recv_count = (count > vrank * scatter_count) ? (count - vrank * scatter_count) : 0;
+#endif
             if (0 == recv_count) {
                 curr_count = 0;
             } else {
@@ -1007,7 +1028,10 @@ int ompi_coll_base_bcast_intra_scatter_allgather_ring(
     mask >>= 1;
     while (mask > 0) {
         if (vrank + mask < comm_size) {
+            send_count = rectify_diff(curr_count, (size_t)(scatter_count * mask));
+#if 0
             send_count = (curr_count > scatter_count * mask) ? (curr_count - scatter_count * mask) : 0;
+#endif
             if (send_count > 0) {
                 int child = (rank + mask) % comm_size;
                 err = MCA_PML_CALL(send((char *)buf + (ptrdiff_t)scatter_count * (vrank + mask) * extent,
@@ -1032,16 +1056,22 @@ int ompi_coll_base_bcast_intra_scatter_allgather_ring(
     for (int i = 1; i < comm_size; ++i) {
         /* how many elements remain in recv_block? */
         size_t recv_offset_elems = recv_block * scatter_count;
+        size_t recv_remaining  = rectify_diff(count, recv_offset_elems);
+#if 0
         size_t recv_remaining = (recv_offset_elems < count) ?
                                    (count - recv_offset_elems) : 0;
+#endif
         recv_count = (recv_remaining < scatter_count) ?
                                     recv_remaining : scatter_count;
         size_t recv_offset = recv_offset_elems * extent;
 
         /* same logic for send */
         size_t send_offset_elems = send_block * scatter_count;
+        size_t send_remaining = rectify_diff(count, send_offset_elems);
+#if 0
         size_t send_remaining = (send_offset_elems < count) ?
                                   (count - send_offset_elems) : 0;
+#endif
         send_count = (send_remaining < scatter_count) ?
                                 send_remaining : scatter_count;
         size_t send_offset = send_offset_elems * extent;
@@ -1051,13 +1081,13 @@ int ompi_coll_base_bcast_intra_scatter_allgather_ring(
                                       (char*)buf + recv_offset, recv_count,
                                       datatype, left, MCA_COLL_BASE_TAG_BCAST,
                                       comm, MPI_STATUS_IGNORE, rank);
-       if (MPI_SUCCESS != err) {
-           goto cleanup_and_return;
-       }
+        if (MPI_SUCCESS != err) {
+            goto cleanup_and_return;
+        }
 
-       /* rotate blocks */
-       send_block = recv_block;
-       recv_block = (recv_block + comm_size - 1) % comm_size;
+        /* rotate blocks */
+        send_block = recv_block;
+        recv_block = (recv_block + comm_size - 1) % comm_size;
     }
 
 cleanup_and_return: