Use a more performant way to get the current thread id (dotnet#95609)

* Fix thread_id perf issue * add an assert to ensure the current thread is not null * FB * Apply suggestions from code review Co-authored-by: Jan Kotas <[email protected]> --------- Co-authored-by: Jan Kotas <[email protected]>
fanyang-mono · Dec 11, 2023 · 07b2b50 · 07b2b50
1 parent e7da682
commit 07b2b50
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Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/src/coreclr/gc/env/gcenv.structs.h b/src/coreclr/gc/env/gcenv.structs.h
@@ -15,8 +15,15 @@ struct GCSystemInfo
 
 typedef void * HANDLE;
 
+// Across all platforms, NativeAOT Thread::GetPalThreadIdForLogging assumes that the thread
+// ID is stored in the first 8 bytes of this structure.
+
 #ifdef TARGET_UNIX
 
+#ifdef FEATURE_NATIVEAOT
+static_assert(sizeof(pthread_t) == sizeof(uint64_t), "EEThreadId layout mismatch");
+#endif
+
 class EEThreadId
 {
     pthread_t m_id;

diff --git a/src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.cpp b/src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.cpp
@@ -399,9 +399,11 @@ ep_rt_thread_id_t
 ep_rt_aot_current_thread_get_id (void)
 {
     STATIC_CONTRACT_NOTHROW;
-
 #ifdef TARGET_UNIX
-    return static_cast<ep_rt_thread_id_t>(PalGetCurrentOSThreadId());
+    static __thread uint64_t tid;
+    if (!tid)
+        tid = PalGetCurrentOSThreadId();
+    return static_cast<ep_rt_thread_id_t>(tid);
 #else
     return static_cast<ep_rt_thread_id_t>(::GetCurrentThreadId ());
 #endif