Improved echo client

Upstream echo clients improvements used by the echo evaluation

apps/EchoClient.cpp

 // SPDX-License-Identifier: LGPL-3.0-or-later
 // Copyright © 2021 Florian Fischer
 #include <fcntl.h>
-#include <netdb.h>			 //for getaddrinfo
+#include <netdb.h>	//for getaddrinfo
+#include <netinet/in.h>
+#include <netinet/tcp.h>
 #include <sys/socket.h>	 // for shutdown, socket, AF_INET
 #include <sys/stat.h>
 #include <unistd.h>
 
 #include <algorithm>	// for find
+#include <array>
 #include <atomic>
 #include <cerrno>		 // for errno, ECANCELED
 #include <chrono>		 // for nanoseconds, duration, durat...
@@ -31,6 +34,9 @@ using emper::io::CloseFuture;
 using emper::io::RecvFuture;
 using emper::io::SendFuture;
 
+using std::chrono::duration_cast;
+using std::chrono::nanoseconds;
+
 // Defaults
 const int DECIMAL = 10;
 const std::string HOST = "0.0.0.0";
@@ -70,8 +76,12 @@ static void clientFunc(uint64_t client_id, Semaphore& readySem, Semaphore& start
 		spawn([&, next_client_id] { clientFunc(next_client_id, readySem, startSem, cps); }, cps);
 	}
 
-	// NOLINTNEXTLINE(modernize-avoid-c-arrays)
-	char* buf[2];
+	int enable = 1;
+	if (setsockopt(client_sock, IPPROTO_TCP, TCP_NODELAY, &enable, sizeof(enable)) == -1) {
+		DIE_MSG_ERRNO("setsockopt failed");
+	}
+
+	std::array<char*, 2> buf;
 	buf[0] = new char[size];
 	buf[1] = new char[size];
 	uint64_t avg_ns = 0;
@@ -116,7 +126,7 @@ static void clientFunc(uint64_t client_id, Semaphore& readySem, Semaphore& start
 			DIE_MSG("got unexpected echo from server");
 		}
 
-		auto duration = std::chrono::duration_cast<std::chrono::nanoseconds>(end - start);
+		auto duration = duration_cast<nanoseconds>(end - start);
 		uint64_t ns = duration.count();
 		if (unlikely(avg_ns == 0)) {
 			avg_ns = ns;
@@ -202,15 +212,7 @@ auto main(int argc, char* argv[]) -> int {
 	}
 
 	int out_fd = STDOUT_FILENO;
-
 	char* output_file = getOption(argc, argv, "-f");
-	if (output_file) {
-		out_fd = open(output_file, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH);
-
-		if (out_fd < 0) {
-			DIE_MSG_ERRNO("opening output file failed");
-		}
-	}
 
 	int err = getaddrinfo(host.c_str(), port.c_str(), nullptr, &server);
 	if (err) {
@@ -230,6 +232,8 @@ auto main(int argc, char* argv[]) -> int {
 		Semaphore readySemaphore;
 		Semaphore startSemaphore;
 
+		auto connect_start = std::chrono::high_resolution_clock::now();
+
 		// start first client batch
 		for (size_t i = 0; i < server_backlog; ++i) {
 			size_t next_client_id = client_ids.fetch_add(1);
@@ -246,6 +250,8 @@ auto main(int argc, char* argv[]) -> int {
 			readySemaphore.acquire();
 		}
 
+		auto echo_start = std::chrono::high_resolution_clock::now();
+
 		// start the clients
 		for (size_t i = 0; i < clients; ++i) {
 			startSemaphore.release();
@@ -254,15 +260,41 @@ auto main(int argc, char* argv[]) -> int {
 		// await the clients
 		cps.wait();
 
+		auto echo_end = std::chrono::high_resolution_clock::now();
+
 		uint64_t avg_ns = client_avgs[0];
 		for (size_t i = 1; i < clients; ++i) {
 			avg_ns += client_avgs[i];
 			avg_ns /= 2;
 		}
 
+		auto connect_duration = duration_cast<nanoseconds>(echo_start - connect_start).count();
+		auto echo_duration = duration_cast<nanoseconds>(echo_end - echo_start).count();
+		auto total_duration = duration_cast<nanoseconds>(echo_end - connect_start).count();
+
 		std::stringstream sst;
-		sst << "clients,iterations,size,time" << std::endl;
-		sst << clients << "," << iterations << "," << size << "," << avg_ns << std::endl;
+		bool exists = true;
+		if (output_file) {
+			exists = access(output_file, W_OK) == 0;
+			int openflags;
+			int mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH;
+			if (!exists) {
+				openflags = O_CREAT | O_WRONLY;
+			} else {
+				openflags = O_APPEND;
+			}
+
+			out_fd = emper::io::openAndWait(output_file, openflags, mode);
+			if (out_fd < 0) {
+				DIE_MSG_ERRNO("opening output file failed");
+			}
+		}
+
+		if (!exists) {
+			sst << "clients,iterations,size,avg_ns,connect,echo,total" << std::endl;
+		}
+		sst << clients << "," << iterations << "," << size << "," << avg_ns << "," << connect_duration
+				<< "," << echo_duration << "," << total_duration << std::endl;
 
 		auto output = sst.str();
 		if (emper::io::writeFileAndWait(out_fd, output.c_str(), output.size()) < 0) {