Add env variable to disable CPU affinity override

New environment variable HSA_OVERRIDE_CPU_AFFINITY_DEBUG to
enable/disable overriding CPU affinity.

Default value is enabled(1).

This is a temporary variable and may be removed in the future.

Change-Id: Id6a7c611730471ddc276ca333fde1e57046bf32a

runtime/hsa-runtime/core/util/flag.h

@@ -159,6 +159,11 @@ class Flag {
 
     var = os::GetEnvVar("HSA_SVM_PROFILE");
     svm_profile_ = var;
+
+    // Temporary environment variable to disable CPU affinity override
+    // Will either rename to HSA_OVERRIDE_CPU_AFFINITY later or remove completely.
+    var = os::GetEnvVar("HSA_OVERRIDE_CPU_AFFINITY_DEBUG");
+    override_cpu_affinity_ = (var == "0") ? false : true;
   }
 
   void parse_masks(uint32_t maxGpu, uint32_t maxCU) {
@@ -212,6 +217,8 @@ class Flag {
 
   bool check_sramecc_validity() const { return check_sramecc_validity_; }
 
+  bool override_cpu_affinity() const { return override_cpu_affinity_; }
+
   XNACK_REQUEST xnack() const { return xnack_; }
 
   bool debug() const { return debug_; }
@@ -252,6 +259,7 @@ class Flag {
   bool cu_mask_skip_init_;
   bool coop_cu_count_;
   bool discover_copy_agents_;
+  bool override_cpu_affinity_;
 
   SDMA_OVERRIDE enable_sdma_;
 

runtime/hsa-runtime/core/util/lnx/os_linux.cpp

@@ -59,6 +59,7 @@
 #include <memory>
 #include <string>
 #include <utility>
+#include "core/inc/runtime.h"
 
 namespace rocr {
 namespace os {
@@ -99,16 +100,18 @@ class os_thread {
       assert(err == 0 && "pthread_attr_setstacksize failed.");
     }
 
-    int cores = get_nprocs_conf();
-    cpu_set_t* cpuset = CPU_ALLOC(cores);
-    for(int i=0; i<cores; i++){
-      CPU_SET(i, cpuset);
+    if (core::Runtime::runtime_singleton_->flag().override_cpu_affinity()) {
+      int cores = get_nprocs_conf();
+      cpu_set_t* cpuset = CPU_ALLOC(cores);
+      for (int i = 0; i < cores; i++) {
+        CPU_SET(i, cpuset);
+      }
+      int err = pthread_attr_setaffinity_np(&attrib, CPU_ALLOC_SIZE(cores), cpuset);
+      assert(err == 0 && "pthread_attr_setaffinity_np failed.");
+      CPU_FREE(cpuset);
     }
-    int err = pthread_attr_setaffinity_np(&attrib, CPU_ALLOC_SIZE(cores), cpuset);
-    assert(err == 0 && "pthread_attr_setaffinity_np failed.");
-    CPU_FREE(cpuset);
 
-    err = pthread_create(&thread, &attrib, ThreadTrampoline, args.get());
+    int err = pthread_create(&thread, &attrib, ThreadTrampoline, args.get());
 
     // Probably a stack size error since system limits can be different from PTHREAD_STACK_MIN
     // Attempt to grow the stack within reason.