Merge remote-tracking branch 'nccl/master' into HEAD

src/include/param.h

@@ -1,6 +1,6 @@
 /*************************************************************************
  * Copyright (c) 2017-2022, NVIDIA CORPORATION. All rights reserved.
- * Modifications Copyright (c) 2019-2022 Advanced Micro Devices, Inc. All rights reserved.
+ * Modifications Copyright (c) 2019-2023 Advanced Micro Devices, Inc. All rights reserved.
  *
  * See LICENSE.txt for license information
  ************************************************************************/
@@ -30,32 +30,16 @@ void ncclLoadParam(char const* env, int64_t deftVal, int64_t uninitialized, int6
 #define RCCL_PARAM_DECLARE(name) \
 int64_t rcclParam##name()
 
-#define RCCL_PARAM(name, env, default_value) \
+#define RCCL_PARAM(name, env, deftVal) \
 pthread_mutex_t rcclParamMutex##name = PTHREAD_MUTEX_INITIALIZER; \
 int64_t rcclParam##name() { \
-  static_assert(default_value != -1LL, "default value cannot be -1"); \
-  static int64_t value = -1LL; \
-  int64_t localValue; \
-  pthread_mutex_lock(&rcclParamMutex##name); \
-  localValue = value; \
-  char* en = getenv("RCCL_TEST_ENV_VARS"); \
-  if (value == -1LL || (en && (strcmp(en, "ENABLE") == 0))){  \
-    value = default_value; \
-    char* str = getenv("RCCL_" env); \
-    if (str && strlen(str) > 0) { \
-      errno = 0; \
-      int64_t v = strtoll(str, NULL, 0); \
-      if (errno) { \
-        INFO(NCCL_ALL,"Invalid value %s for %s, using default %lu.", str, "RCCL_" env, value); \
-      } else { \
-        value = v; \
-        INFO(NCCL_ALL,"%s set by environment to %lu.", "RCCL_" env, value);  \
-      } \
+    constexpr int64_t uninitialized = INT64_MIN; \
+    static_assert(deftVal != uninitialized, "default value cannot be the uninitialized value."); \
+    static int64_t cache = uninitialized; \
+    if (__builtin_expect(__atomic_load_n(&cache, __ATOMIC_RELAXED) == uninitialized, false)) { \
+      ncclLoadParam("RCCL_" env, deftVal, uninitialized, &cache); \
     } \
-    localValue = value; \
-  } \
-  pthread_mutex_unlock(&rcclParamMutex##name); \
-  return localValue; \
-}
+    return cache; \
+  }
 
 #endif