[libc-commits] [PATCH] D150456: [libc] Check the RPC server once again after the kernel exits

[Joseph Huber via Phabricator via libc-commits]

jhuber6 created this revision.
jhuber6 added reviewers: tianshilei1992, JonChesterfield, sivachandra, michaelrj, lntue.
Herald added subscribers: libc-commits, mattd, asavonic, ecnelises, kerbowa, tschuett, jvesely.
Herald added projects: libc-project, All.
jhuber6 requested review of this revision.

We support asynchronous sends, that means that the kernel can issue a
send, then exit the kernel as we do with the `EXIT` syscall. Because of
the condition it's therefore possible for the kernel to exit and break
from the loop before we check the server again. This can potentially
cause us to ignore an `EXIT` call from the GPU.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D150456

Files:
  libc/utils/gpu/loader/amdgpu/Loader.cpp
  libc/utils/gpu/loader/nvptx/Loader.cpp


Index: libc/utils/gpu/loader/nvptx/Loader.cpp
===================================================================
--- libc/utils/gpu/loader/nvptx/Loader.cpp
+++ libc/utils/gpu/loader/nvptx/Loader.cpp
@@ -186,6 +186,10 @@
   while (cuStreamQuery(stream) == CUDA_ERROR_NOT_READY)
     handle_server();
 
+  // Handle the server one more time in case the kernel exited with a pending
+  // send still in flight.
+  handle_server();
+
   return CUDA_SUCCESS;
 }
 
Index: libc/utils/gpu/loader/amdgpu/Loader.cpp
===================================================================
--- libc/utils/gpu/loader/amdgpu/Loader.cpp
+++ libc/utils/gpu/loader/amdgpu/Loader.cpp
@@ -221,6 +221,10 @@
              /*timeout_hint=*/1024, HSA_WAIT_STATE_ACTIVE) != 0)
     handle_server();
 
+  // Handle the server one more time in case the kernel exited with a pending
+  // send still in flight.
+  handle_server();
+
   // Destroy the resources acquired to launch the kernel and return.
   if (hsa_status_t err = hsa_amd_memory_pool_free(args))
     handle_error(err);


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