Fix for KMP_AFFINITY=disabled and KMP_TOPOLOGY_METHOD=hwloc

[jlpeyton]

Summary

With these settings, the create_hwloc_map() method was being called causing an
assert(). After some consideration, it was determined that disabling affinity
explicitly should just disable hwloc as well. i.e., KMP_AFFINITY overrides
KMP_TOPOLOGY_METHOD. This lets the user know that the Hwloc mechanism is being
ignored when KMP_AFFINITY=disabled.

[jlpeyton]

Ping

[tlwilmar]

LGTM

openmp/trunk/runtime/src/kmp_affinity.cpp

 void *KMPAffinity::operator new(size_t n) { return __kmp_allocate(n); }
 void KMPAffinity::operator delete(void *p) { __kmp_free(p); }
 
 void KMPAffinity::pick_api() {
   KMPAffinity *affinity_dispatch;
   if (picked_api)
     return;
 #if KMP_USE_HWLOC
-  if (__kmp_affinity_top_method == affinity_top_method_hwloc) {
+  // Only use Hwloc if affinity isn't explicitly disabled and
+  // user requests Hwloc topology method
+  if (__kmp_affinity_top_method == affinity_top_method_hwloc &&
+      __kmp_affinity_type != affinity_disabled) {
     affinity_dispatch = new KMPHwlocAffinity();
   } else
 #endif
   {
     affinity_dispatch = new KMPNativeAffinity();
   }
   __kmp_affinity_dispatch = affinity_dispatch;
   picked_api = true;

openmp/trunk/runtime/src/kmp_settings.cpp

 
 #if KMP_AFFINITY_SUPPORTED
 
   if (!TCR_4(__kmp_init_middle)) {
     // Determine if the machine/OS is actually capable of supporting
     // affinity.
     const char *var = "KMP_AFFINITY";
     KMPAffinity::pick_api();
+#if KMP_USE_HWLOC
+    // If Hwloc topology discovery was requested but affinity was also disabled,
+    // then tell user that Hwloc request is being ignored and use default
+    // topology discovery method.
+    if (__kmp_affinity_top_method == affinity_top_method_hwloc &&
+        __kmp_affinity_dispatch->get_api_type() != KMPAffinity::HWLOC) {
+      KMP_WARNING(AffIgnoringHwloc, var);
+      __kmp_affinity_top_method = affinity_top_method_all;
+    }
+#endif
     if (__kmp_affinity_type == affinity_disabled) {
       KMP_AFFINITY_DISABLE();
     } else if (!KMP_AFFINITY_CAPABLE()) {
       __kmp_affinity_dispatch->determine_capable(var);
       if (!KMP_AFFINITY_CAPABLE()) {
         if (__kmp_affinity_verbose ||
             (__kmp_affinity_warnings &&
              (__kmp_affinity_type != affinity_default) &&

openmp/trunk/runtime/test/env/kmp_aff_disable_hwloc.c

+// RUN: %libomp-compile && env KMP_AFFINITY=disabled KMP_TOPOLOGY_METHOD=hwloc %libomp-run
+// REQUIRES: hwloc
+#include <stdio.h>
+#include <stdlib.h>
+
+// Test will assert() without fix
+int test_affinity_disabled_plus_hwloc() {
+  #pragma omp parallel
+  {}
+  return 1;
+}
+
+int main(int argc, char **argv) {
+  int i, j;
+  int failed = 0;
+
+  if (!test_affinity_disabled_plus_hwloc()) {
+    failed = 1;
+  }
+  return failed;
+}

openmp/trunk/runtime/test/lit.cfg

 config.target_triple = [ ]
 if re.search('gcc', config.test_compiler) is not None:
     config.available_features.add('gcc')
 
 # Setup environment to find dynamic library at runtime
 append_dynamic_library_path(config.library_dir)
 if config.using_hwloc:
     append_dynamic_library_path(config.hwloc_library_dir)
+    config.available_features.add('hwloc')
 
 # Rpath modifications for Darwin
 if config.operating_system == 'Darwin':
     config.test_cflags += " -Wl,-rpath," + config.library_dir
     if config.using_hwloc:
         config.test_cflags += " -Wl,-rpath," + config.hwloc_library_dir
 
 # Find the SDK on Darwin