htrdr

commit 0e7bf16d5b891fd43e91b9d496c18229913228c3
parent 2125a45c2cd1a06fdc5574ad5e27e3e04eaac6e0
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Mon,  6 Apr 2020 15:00:48 +0200

Fix a deadlock when htrdr is with MPI

Diffstat:
M
src/htrdr_draw_radiance.c
 | 
16
++++++++++++----

1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/src/htrdr_draw_radiance.c b/src/htrdr_draw_radiance.c
@@ -898,10 +898,18 @@ draw_image
 
   if(ATOMIC_GET(&res) != RES_OK) goto error;
 
-  /* Synchronize the process */
-  mutex_lock(htrdr->mpi_mutex);
-  MPI(Barrier(MPI_COMM_WORLD));
-  mutex_unlock(htrdr->mpi_mutex);
+  /* Asynchronously wait for processes completion. Use an asynchronous barrier to
+   * avoid a dead lock with the `mpi_probe_thieves' thread that requires also
+   * the `mpi_mutex'. */
+  {
+    MPI_Request req;
+
+    mutex_lock(htrdr->mpi_mutex);
+    MPI(Ibarrier(MPI_COMM_WORLD, &req));
+    mutex_unlock(htrdr->mpi_mutex);
+
+    mpi_wait_for_request(htrdr, &req);
+  }
 
 exit:
   if(rng_proc) SSP(rng_ref_put(rng_proc));