New API for restoring current thread's affinity to init affinity of application
This new API, int kmp_set_thread_affinity_mask_initial(), is available for use
by other parallel runtime libraries inside a possibly OpenMP-registered thread.
This entry point restores the current thread's affinity mask to the affinity
mask of the application when it first began. If -1 is returned it can be assumed
that either the thread hasn't called affinity initialization or that the thread
isn't registered with the OpenMP library. If 0 is returned then, then the call
was successful. Any return value greater than zero indicates an error occurred
when setting affinity.
Differential Revision: http://reviews.llvm.org/D15867
llvm-svn: 257489
diff --git a/openmp/runtime/src/kmp_affinity.cpp b/openmp/runtime/src/kmp_affinity.cpp
index 4e6699f..0dc6f73 100644
--- a/openmp/runtime/src/kmp_affinity.cpp
+++ b/openmp/runtime/src/kmp_affinity.cpp
@@ -4732,4 +4732,42 @@
}
}
+#if KMP_OS_LINUX
+// We don't need this entry for Windows because
+// there is GetProcessAffinityMask() api
+//
+// The intended usage is indicated by these steps:
+// 1) The user gets the current affinity mask
+// 2) Then sets the affinity by calling this function
+// 3) Error check the return value
+// 4) Use non-OpenMP parallelization
+// 5) Reset the affinity to what was stored in step 1)
+#ifdef __cplusplus
+extern "C"
+#endif
+int
+kmp_set_thread_affinity_mask_initial()
+// the function returns 0 on success,
+// -1 if we cannot bind thread
+// >0 (errno) if an error happened during binding
+{
+ int gtid = __kmp_get_gtid();
+ if (gtid < 0) {
+ // Do not touch non-omp threads
+ KA_TRACE(30, ( "kmp_set_thread_affinity_mask_initial: "
+ "non-omp thread, returning\n"));
+ return -1;
+ }
+ if (!KMP_AFFINITY_CAPABLE() || !__kmp_init_middle) {
+ KA_TRACE(30, ( "kmp_set_thread_affinity_mask_initial: "
+ "affinity not initialized, returning\n"));
+ return -1;
+ }
+ KA_TRACE(30, ( "kmp_set_thread_affinity_mask_initial: "
+ "set full mask for thread %d\n", gtid));
+ KMP_DEBUG_ASSERT(fullMask != NULL);
+ return __kmp_set_system_affinity(fullMask, FALSE);
+}
+#endif
+
#endif // KMP_AFFINITY_SUPPORTED