[Openmp-commits] [PATCH] D40357: Enable thread affinity for Power

[Jonas Hahnfeld via Phabricator via Openmp-commits]

Hahnfeld created this revision.

To make this work according to the OpenMP spec, the runtime needs
information about the hardware topology. On Linux the default way
is to parse /proc/cpuinfo which contains this information for x86
machines but (at least) not for Power architectures.

Fortunately, there is a different code path which is able to get
that data from sysfs. The needed patch has landed in 2006 for
Linux 2.6.16 which is safe to assume nowadays (even RHEL 5 had
a kernel version derived from 2.6.18, and we are now at RHEL 7!).


https://reviews.llvm.org/D40357

Files:
  runtime/src/kmp_affinity.cpp
  runtime/src/kmp_os.h


Index: runtime/src/kmp_os.h
===================================================================
--- runtime/src/kmp_os.h
+++ runtime/src/kmp_os.h
@@ -61,7 +61,7 @@
 #error Unknown compiler
 #endif
 
-#if (KMP_OS_LINUX || KMP_OS_WINDOWS) && !KMP_OS_CNK && !KMP_ARCH_PPC64
+#if (KMP_OS_LINUX || KMP_OS_WINDOWS) && !KMP_OS_CNK
 #define KMP_AFFINITY_SUPPORTED 1
 #if KMP_OS_WINDOWS && KMP_ARCH_X86_64
 #define KMP_GROUP_AFFINITY 1
@@ -859,9 +859,6 @@
 #endif
 
 // Switches for OSS builds
-#ifndef USE_SYSFS_INFO
-#define USE_SYSFS_INFO 0
-#endif
 #ifndef USE_CMPXCHG_FIX
 #define USE_CMPXCHG_FIX 1
 #endif
Index: runtime/src/kmp_affinity.cpp
===================================================================
--- runtime/src/kmp_affinity.cpp
+++ runtime/src/kmp_affinity.cpp
@@ -1836,7 +1836,7 @@
         if (threadInfo[num_avail][osIdIndex] != UINT_MAX)
           goto dup_field;
         threadInfo[num_avail][osIdIndex] = val;
-#if KMP_OS_LINUX && USE_SYSFS_INFO
+#if KMP_OS_LINUX && !(KMP_ARCH_X86 || KMP_ARCH_X86_64)
         char path[256];
         KMP_SNPRINTF(
             path, sizeof(path),


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