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Stack allocate the RPC Request

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Summary:
There's no need to heap allocate the request which is used only to be
serialized and sent over the network. Unfortunately, this change
complicates the reading a bit, because we need to deserialize the raw
pointer and put it in std::unique_ptr instead of simply deserializing
the unique_ptr.

Heap allocation shows up visibly in perf during benchmarks, so this
change may yield some improvement.

Reviewers: mferencevic, mtomic

Reviewed By: mferencevic

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D1254
This commit is contained in:
Teon Banek 2018-02-28 10:52:22 +01:00
parent e61bb8ab1e
commit b7f77d40ad
3 changed files with 13 additions and 9 deletions
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6
src/communication/rpc/client.cpp
View File

@ -19,7 +19,7 @@ namespace communication::rpc {
Client::Client(const io::network::Endpoint &endpoint) : endpoint_(endpoint) {}
std::unique_ptr<Message> Client::Call(std::unique_ptr<Message> request) {
std::unique_ptr<Message> Client::Call(const Message &request) {
std::lock_guard<std::mutex> guard(mutex_);
if (FLAGS_rpc_random_latency) {
@ -50,7 +50,9 @@ std::unique_ptr<Message> Client::Call(std::unique_ptr<Message> request) {
std::stringstream request_stream(std::ios_base::out | std::ios_base::binary);
{
boost::archive::binary_oarchive request_archive(request_stream);
request_archive << request;
// Serialize reference as pointer (to serialize the derived class). The
// request is read in protocol.cpp.
request_archive << &request;
// Archive destructor ensures everything is written.
}

5
src/communication/rpc/client.hpp
View File

@ -36,8 +36,7 @@ class Client {
utils::Demangle(typeid(Req).name()).value_or("unknown"));
std::unique_ptr<Message> response = nullptr;
stats::Stopwatch(request_name, [&] {
response = Call(std::unique_ptr<Message>(
std::make_unique<Req>(std::forward<Args>(args)...)));
response = Call(Req(std::forward<Args>(args)...));
});
auto *real_response = dynamic_cast<Res *>(response.get());
if (!real_response && response) {
@ -55,7 +54,7 @@ class Client {
void Abort();
private:
std::unique_ptr<Message> Call(std::unique_ptr<Message> request);
std::unique_ptr<Message> Call(const Message &request);
io::network::Endpoint endpoint_;
std::experimental::optional<io::network::Socket> socket_;

11
src/communication/rpc/protocol.cpp
View File

@ -24,15 +24,18 @@ void Session::Execute() {
buffer_.Resize(request_size);
if (buffer_.size() < request_size) return;
std::unique_ptr<Message> request;
{
// Read the request message.
std::unique_ptr<Message> request([this, request_len]() {
Message *req_ptr = nullptr;
std::stringstream stream(std::ios_base::in | std::ios_base::binary);
stream.str(std::string(
reinterpret_cast<char *>(buffer_.data() + sizeof(MessageSize)),
request_len));
boost::archive::binary_iarchive archive(stream);
archive >> request;
}
// Sent from client.cpp
archive >> req_ptr;
return req_ptr;
}());
buffer_.Shift(sizeof(MessageSize) + request_len);
auto callbacks_accessor = server_.callbacks_.access();