[RunHandler] Minor optimizations to environment variable handling.
1. Avoid re-evaluating the "TF_RUN_HANDLER_USE_SUB_THREAD_POOL" environment variable each time a task is enqueued, by caching the result in a static local variable.
2. A similar optimization in `ChooseRequestsWithExponentialDistribution()`.
3. Since all the arguments are string literals, we can pass `const char*` to the `ParamFromEnv*WithDefault()` methods, to avoid creating a temporary `std::string` on each call.
PiperOrigin-RevId: 308915732
Change-Id: I1642b5d924477eb006497acf95ac7cfc17956feb
diff --git a/tensorflow/core/framework/run_handler.cc b/tensorflow/core/framework/run_handler.cc
index c0ab50f..bf3b14a 100644
--- a/tensorflow/core/framework/run_handler.cc
+++ b/tensorflow/core/framework/run_handler.cc
@@ -167,7 +167,7 @@
}
Waiter* w = nullptr;
- bool use_sub_thread_pool =
+ static const bool use_sub_thread_pool =
ParamFromEnvBoolWithDefault("TF_RUN_HANDLER_USE_SUB_THREAD_POOL", false);
Waiter* waiter_queue;
@@ -424,7 +424,8 @@
// thread_work_sources are order as start_request_idx, 0, 2, 4 ... 1, 3,
// 5... for half of the threads and start_request_idx, 1, 3, 5 ... 0, 2,
// 4... for the other half of the threads.
- int num_shards = ParamFromEnvWithDefault("TF_RUN_HANDLER_QUEUE_SHARDS", 1);
+ static const int num_shards =
+ ParamFromEnvWithDefault("TF_RUN_HANDLER_QUEUE_SHARDS", 1);
int token = tid % num_shards;
for (int i = 0; i < num_shards; ++i) {
for (int j = token; j < thread_work_sources.size(); j += num_shards) {
diff --git a/tensorflow/core/framework/run_handler_util.cc b/tensorflow/core/framework/run_handler_util.cc
index c832a64..932fb4a 100644
--- a/tensorflow/core/framework/run_handler_util.cc
+++ b/tensorflow/core/framework/run_handler_util.cc
@@ -23,16 +23,15 @@
namespace tensorflow {
-double ParamFromEnvWithDefault(const std::string& var_name,
- double default_value) {
- const char* val = std::getenv(var_name.c_str());
+double ParamFromEnvWithDefault(const char* var_name, double default_value) {
+ const char* val = std::getenv(var_name);
double num;
return (val && strings::safe_strtod(val, &num)) ? num : default_value;
}
-std::vector<double> ParamFromEnvWithDefault(const std::string& var_name,
+std::vector<double> ParamFromEnvWithDefault(const char* var_name,
std::vector<double> default_value) {
- const char* val = std::getenv(var_name.c_str());
+ const char* val = std::getenv(var_name);
if (!val) {
return default_value;
}
@@ -51,9 +50,9 @@
return result;
}
-std::vector<int> ParamFromEnvWithDefault(const std::string& var_name,
+std::vector<int> ParamFromEnvWithDefault(const char* var_name,
std::vector<int> default_value) {
- const char* val = std::getenv(var_name.c_str());
+ const char* val = std::getenv(var_name);
if (!val) {
return default_value;
}
@@ -72,9 +71,8 @@
return result;
}
-bool ParamFromEnvBoolWithDefault(const std::string& var_name,
- bool default_value) {
- const char* val = std::getenv(var_name.c_str());
+bool ParamFromEnvBoolWithDefault(const char* var_name, bool default_value) {
+ const char* val = std::getenv(var_name);
return (val) ? str_util::Lowercase(val) == "true" : default_value;
}
@@ -148,19 +146,20 @@
static const double kPowerBase =
ParamFromEnvWithDefault("TF_RUN_HANDLER_EXP_DIST_POWER_BASE", 2.0);
+ static const int kMinEvenThreadsFromEnv = static_cast<int>(
+ ParamFromEnvWithDefault("TF_RUN_HANDLER_EXP_DIST_MIN_EVEN_THREADS", 1));
+ static const int kMaxEvenThreadsFromEnv = static_cast<int>(
+ ParamFromEnvWithDefault("TF_RUN_HANDLER_EXP_DIST_MAX_EVEN_THREADS", 3));
+
std::vector<int> request_idx_list;
request_idx_list.resize(num_threads);
// Each request gets at least this number of threads that steal from it first.
int min_threads_per_request =
num_threads * kCapacityFractionForEvenDistribution / num_active_requests;
min_threads_per_request =
- std::max(static_cast<int>(ParamFromEnvWithDefault(
- "TF_RUN_HANDLER_EXP_DIST_MIN_EVEN_THREADS", 1)),
- min_threads_per_request);
+ std::max(kMinEvenThreadsFromEnv, min_threads_per_request);
min_threads_per_request =
- std::min(static_cast<int>(ParamFromEnvWithDefault(
- "TF_RUN_HANDLER_EXP_DIST_MAX_EVEN_THREADS", 3)),
- min_threads_per_request);
+ std::min(kMaxEvenThreadsFromEnv, min_threads_per_request);
int num_remaining_threads =
std::max(0, num_threads - num_active_requests * min_threads_per_request);
diff --git a/tensorflow/core/framework/run_handler_util.h b/tensorflow/core/framework/run_handler_util.h
index 982f06f..c63583d 100644
--- a/tensorflow/core/framework/run_handler_util.h
+++ b/tensorflow/core/framework/run_handler_util.h
@@ -56,25 +56,23 @@
// Look up environment variable named 'var_name' and return the value if it
// exist and can be parsed. Return 'default_value' otherwise.
-double ParamFromEnvWithDefault(const std::string& var_name,
- double default_value);
+double ParamFromEnvWithDefault(const char* var_name, double default_value);
// Look up environment variable named 'var_name' and return the value if it
// exist and can be parsed. The value must be in format val1,val2... Return
// 'default_value' otherwise.
-std::vector<double> ParamFromEnvWithDefault(const std::string& var_name,
+std::vector<double> ParamFromEnvWithDefault(const char* var_name,
std::vector<double> default_value);
// Look up environment variable named 'var_name' and return the value if it
// exist and can be parsed. The value must be in format val1,val2... Return
// 'default_value' otherwise.
-std::vector<int> ParamFromEnvWithDefault(const std::string& var_name,
+std::vector<int> ParamFromEnvWithDefault(const char* var_name,
std::vector<int> default_value);
// Look up environment variable named 'var_name' and return the value if it
// exist and can be parsed. Return 'default_value' otherwise.
-bool ParamFromEnvBoolWithDefault(const std::string& var_name,
- bool default_value);
+bool ParamFromEnvBoolWithDefault(const char* var_name, bool default_value);
} // end namespace tensorflow
#endif // TENSORFLOW_CORE_FRAMEWORK_RUN_HANDLER_UTIL_H_
