Pluck some low hanging concurrency fruit
Make the shutdown flag on servers be per thread to save contention on
the lock that must guard it.
diff --git a/test/cpp/qps/server_async.cc b/test/cpp/qps/server_async.cc
index 210aef4..f5251e9 100644
--- a/test/cpp/qps/server_async.cc
+++ b/test/cpp/qps/server_async.cc
@@ -64,7 +64,7 @@
class AsyncQpsServerTest : public Server {
public:
- AsyncQpsServerTest(const ServerConfig &config, int port) : shutdown_(false) {
+ AsyncQpsServerTest(const ServerConfig &config, int port) {
char *server_address = NULL;
gpr_join_host_port(&server_address, "::", port);
@@ -97,6 +97,9 @@
}
}
for (int i = 0; i < config.threads(); i++) {
+ shutdown_state_.emplace_back(new PerThreadShutdownState());
+ }
+ for (int i = 0; i < config.threads(); i++) {
threads_.push_back(std::thread([=]() {
// Wait until work is available or we are shutting down
bool ok;
@@ -105,11 +108,9 @@
ServerRpcContext *ctx = detag(got_tag);
// The tag is a pointer to an RPC context to invoke
bool still_going = ctx->RunNextState(ok);
- std::unique_lock<std::mutex> g(shutdown_mutex_);
- if (!shutdown_) {
+ if (!shutdown_state_[i]->shutdown()) {
// this RPC context is done, so refresh it
if (!still_going) {
- g.unlock();
ctx->Reset();
}
} else {
@@ -122,9 +123,8 @@
}
~AsyncQpsServerTest() {
server_->Shutdown();
- {
- std::lock_guard<std::mutex> g(shutdown_mutex_);
- shutdown_ = true;
+ for (auto ss = shutdown_state_.begin(); ss != shutdown_state_.end(); ++ss) {
+ (*ss)->set_shutdown();
}
for (auto thr = threads_.begin(); thr != threads_.end(); thr++) {
thr->join();
@@ -316,8 +316,25 @@
TestService::AsyncService async_service_;
std::forward_list<ServerRpcContext *> contexts_;
- std::mutex shutdown_mutex_;
- bool shutdown_;
+ class PerThreadShutdownState {
+ public:
+ PerThreadShutdownState() : shutdown_(false) {}
+
+ bool shutdown() const {
+ std::lock_guard<std::mutex> lock(mutex_);
+ return shutdown_;
+ }
+
+ void set_shutdown() {
+ std::lock_guard<std::mutex> lock(mutex_);
+ shutdown_ = true;
+ }
+
+ private:
+ mutable std::mutex mutex_;
+ bool shutdown_;
+ };
+ std::vector<std::unique_ptr<PerThreadShutdownState>> shutdown_state_;
};
std::unique_ptr<Server> CreateAsyncServer(const ServerConfig &config,