[llvm] cd53ded - [Support] Fix computeHostNumPhysicalCores() to respect affinity
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Fri Jul 31 11:20:35 PDT 2020
Author: Fangrui Song
Date: 2020-07-31T11:20:15-07:00
New Revision: cd53ded557c3487b8dae2f9de894fdb5b75cb8c8
URL: https://github.com/llvm/llvm-project/commit/cd53ded557c3487b8dae2f9de894fdb5b75cb8c8
DIFF: https://github.com/llvm/llvm-project/commit/cd53ded557c3487b8dae2f9de894fdb5b75cb8c8.diff
LOG: [Support] Fix computeHostNumPhysicalCores() to respect affinity
computeHostNumPhysicalCores() is designed to respect CPU affinity.
D84764 used sysconf(_SC_NPROCESSORS_ONLN) which does not respect
affinity.
SupportTests Threading.PhysicalConcurrency may fail if taskset -c is specified.
Added:
Modified:
llvm/lib/Support/Host.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Support/Host.cpp b/llvm/lib/Support/Host.cpp
index 01ede62c755a..d3b255ae0f2e 100644
--- a/llvm/lib/Support/Host.cpp
+++ b/llvm/lib/Support/Host.cpp
@@ -1271,11 +1271,14 @@ int computeHostNumPhysicalCores() {
}
return CPU_COUNT(&Enabled);
}
-#elif (defined(__linux__) && \
- (defined(__ppc__) || defined(__powerpc__) || defined(__s390x__)))
-#include <unistd.h>
-
-// Gets the number of *physical cores* on the machine.
+#elif defined(__linux__) && defined(__powerpc__)
+int computeHostNumPhysicalCores() {
+ cpu_set_t Affinity;
+ if (sched_getaffinity(0, sizeof(Affinity), &Affinity) != 0)
+ return -1;
+ return CPU_COUNT(&Affinity);
+}
+#elif defined(__linux__) && defined(__s390x__)
int computeHostNumPhysicalCores() { return sysconf(_SC_NPROCESSORS_ONLN); }
#elif defined(__APPLE__) && defined(__x86_64__)
#include <sys/param.h>
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