[EchoClient] add network barrier support to synchronize multiple clients

apps/EchoClient.cpp

@@ -36,9 +36,7 @@
 #include "lib/math.hpp"
 
 using emper::Semaphore;
-using emper::io::CloseFuture;
-using emper::io::RecvFuture;
-using emper::io::SendFuture;
+using namespace emper::io;
 
 using emper::lib::math::RunningAverage;
 
@@ -76,6 +74,22 @@ bool sendQuit = true;
 std::atomic<bool> terminate = false;
 
 struct addrinfo* server;
+struct addrinfo* coordinator;
+std::string COORDINATOR_PORT = "12346";
+
+static auto getFirstAddrInfo(const std::string& host, const std::string& port) -> struct addrinfo* {
+	struct addrinfo* addrinfo;
+	int err = getaddrinfo(host.c_str(), port.c_str(), nullptr, &addrinfo);
+	if (err) {
+		if (err == EAI_SYSTEM) {
+			DIE_MSG_ERRNO("getaddrinfo failed");
+		} else {
+			LOGE("error in getaddrinfo: " << gai_strerror(err));
+			exit(EXIT_FAILURE);
+		}
+	}
+	return addrinfo;
+}
 
 struct TimeStamps {
 	high_resolution_clock::time_point start;
@@ -168,7 +182,7 @@ class Client {
 
 	void onCONNRESET() {
 		LOGW("Client " << id << " reconnecting");
-		close(sock);
+		closeAndForget(sock);
 		// reconnect to try again
 		connect();
 	}
@@ -387,6 +401,7 @@ static void printUsage(char* name) {
 			<< "Usage: " << name
 			<< "[-h] [-p <port>] [-c <clients>] [-a <address>] [-s <size>] [-b <server backlog>]"
 				 " [-f <output-file>]  [-i <iterations> | -t <execution time in sec>] [--linked-futures]"
+				 " [--coordinator <coordinator-host>"
 			<< std::endl;
 }
 
@@ -476,7 +491,7 @@ auto main(int argc, char* argv[]) -> int {
 			DIE_MSG("Output file: " << output_file << " already exists");
 		}
 
-		out_fd = open(output_file, OPENFLAGS, OPENMODE);
+		out_fd = ::open(output_file, OPENFLAGS, OPENMODE);
 		if (out_fd < 0) {
 			DIE_MSG_ERRNO("opening output file failed");
 		}
@@ -497,22 +512,19 @@ auto main(int argc, char* argv[]) -> int {
 			DIE_MSG("Histogram file: " << histogram_file << " already exists");
 		}
 
-		histogram_fd = open(histogram_file, OPENFLAGS, OPENMODE);
+		histogram_fd = ::open(histogram_file, OPENFLAGS, OPENMODE);
 		if (histogram_fd < 0) {
 			DIE_MSG_ERRNO("opening histogram file failed");
 		}
 	}
 
-	int err = getaddrinfo(host.c_str(), port.c_str(), nullptr, &server);
-	if (err) {
-		if (err == EAI_SYSTEM) {
-			DIE_MSG_ERRNO("getaddrinfo failed");
-		} else {
-			LOGE("error in getaddrinfo: " << gai_strerror(err));
-			exit(EXIT_FAILURE);
-		}
+	char* coordinator_s = getOption(argc, argv, "--coordinator");
+	if (coordinator_s) {
+		coordinator = getFirstAddrInfo(coordinator_s, COORDINATOR_PORT);
 	}
 
+	server = getFirstAddrInfo(host, port);
+
 	printIp(server->ai_addr);
 	printSettings();
 
@@ -541,6 +553,29 @@ auto main(int argc, char* argv[]) -> int {
 			readySemaphore.acquire();
 		}
 
+		// synchronize with other peers using the coordinator
+		if (coordinator) {
+			int conn = socket(coordinator->ai_family, coordinator->ai_socktype, coordinator->ai_protocol);
+			if (conn < 0) DIE_MSG_ERRNO("coordinator socket creation failed");
+
+			int err = emper::io::connectAndWait(conn, coordinator->ai_addr, coordinator->ai_addrlen);
+			if (err) DIE_MSG_ERRNO("coordinator socket connect failed");
+
+			std::string m = "OK";
+			SendFuture sf(conn, m.c_str(), m.size(), 0);
+
+			std::array<char, 16> buf;
+			RecvFuture rf(conn, buf.data(), buf.size(), 0);
+
+			rf.setDependency(sf);
+			err = rf.submitAndWait();
+			if (err < 0) DIE_MSG("coordinator recv failed: " << strerror(-err));
+
+			closeAndForget(conn);
+
+			LOGI("Coordinator go received");
+		}
+
 		high_resolution_clock::time_point echoTerminationTime;
 		if (execution_seconds) {
 			iterations = SIZE_MAX;

apps/EchoServer.cpp

@@ -93,5 +93,5 @@ auto main(int argc, char* argv[]) -> int {
 
 	runtime.waitUntilFinished();
 
-	return EXIT_FAILURE;
+	return EXIT_SUCCESS;
 }