[Openmp-commits] [openmp] 916a915 - [OpenMP] Assign thread ids in the cpuinfo topology method (#91013)

[via Openmp-commits]

Author: Jonathan Peyton
Date: 2024-07-29T09:52:02-05:00
New Revision: 916a91578f7b367c106859a0b46d8ce573bce36a

URL: https://github.com/llvm/llvm-project/commit/916a91578f7b367c106859a0b46d8ce573bce36a
DIFF: https://github.com/llvm/llvm-project/commit/916a91578f7b367c106859a0b46d8ce573bce36a.diff

LOG: [OpenMP] Assign thread ids in the cpuinfo topology method (#91013)

On non-hyperthreaded machines, the thread id is not always explicit in
the /proc/cpuinfo file. This patch adds a check to ensure the thread ids
are put in.

Added: 
    

Modified: 
    openmp/runtime/src/kmp_affinity.cpp

Removed: 
    


################################################################################
diff  --git a/openmp/runtime/src/kmp_affinity.cpp b/openmp/runtime/src/kmp_affinity.cpp
index e6d00ed08702d..ab13ac4f43596 100644
--- a/openmp/runtime/src/kmp_affinity.cpp
+++ b/openmp/runtime/src/kmp_affinity.cpp
@@ -3841,6 +3841,32 @@ static bool __kmp_affinity_create_cpuinfo_map(int *line,
   __kmp_free(counts);
   CLEANUP_THREAD_INFO;
   __kmp_topology->sort_ids();
+
+  int tlevel = __kmp_topology->get_level(KMP_HW_THREAD);
+  if (tlevel > 0) {
+    // If the thread level does not have ids, then put them in.
+    if (__kmp_topology->at(0).ids[tlevel] == kmp_hw_thread_t::UNKNOWN_ID) {
+      __kmp_topology->at(0).ids[tlevel] = 0;
+    }
+    for (int i = 1; i < __kmp_topology->get_num_hw_threads(); ++i) {
+      kmp_hw_thread_t &hw_thread = __kmp_topology->at(i);
+      if (hw_thread.ids[tlevel] != kmp_hw_thread_t::UNKNOWN_ID)
+        continue;
+      kmp_hw_thread_t &prev_hw_thread = __kmp_topology->at(i - 1);
+      // Check if socket, core, anything above thread level changed.
+      // If the ids did change, then restart thread id at 0
+      // Otherwise, set thread id to prev thread's id + 1
+      for (int j = 0; j < tlevel; ++j) {
+        if (hw_thread.ids[j] != prev_hw_thread.ids[j]) {
+          hw_thread.ids[tlevel] = 0;
+          break;
+        }
+      }
+      if (hw_thread.ids[tlevel] == kmp_hw_thread_t::UNKNOWN_ID)
+        hw_thread.ids[tlevel] = prev_hw_thread.ids[tlevel] + 1;
+    }
+  }
+
   if (!__kmp_topology->check_ids()) {
     kmp_topology_t::deallocate(__kmp_topology);
     __kmp_topology = nullptr;