ppd/dsmbr/dsmbr.cc

#include <sys/types.h>
#include <sys/param.h>
#include <sys/cpuset.h>
#include <sys/event.h>
#include <sys/queue.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <netinet/tcp.h>

#include <arpa/inet.h>
#include <bsock/bsock.h>
#include <errno.h>
#include <netdb.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <pthread.h>
#include <pthread_np.h>
#include <semaphore.h>
#include <unistd.h>

#include "dmsg.hh"
#include "generator.hh"
#include "io.hh"
#include "logger.h"
#include "mod.h"
#include "msg.hh"
#include "util.h"

#include <atomic>
#include <cerrno>
#include <csignal>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <list>
#include <set>
#include <sstream>
#include <thread>
#include <unordered_map>
#include <vector>

LOGGER_VAR_DECL;

static constexpr int MAX_MOD_ARGS = 32;
static constexpr int MAX_MOD_ARG_LEN = 128;
static constexpr int MAX_SLAVES = 32;
static constexpr int NEVENT = 64;
static constexpr int CTRL_PORT = 15545;
static constexpr int CTRL_TIMEOUT = 3;
static constexpr int CTRL_BACKLOG = 4096;
static constexpr int BSOCK_BUF_SZ = 4096;
static constexpr int THRD_INIT_PARALLEL = 2;
static constexpr int TIMER_MAGIC = 0x123456;

static constexpr int STATE_WAITING = 0;
static constexpr int STATE_RUN = 1;
static constexpr int STATE_STOP = 2;

struct dsmbr_thread_ctx {
	int tid;
	int core;
	std::list<struct dsmbr_request_record *> stats;
	pthread_t thrd;
};

struct dsmbr_request_record {
	uint64_t recv_size;
	uint64_t send_size;
	uint64_t send_ts;
	uint64_t recv_ts;
};

struct dsmbr_conn {
	Generator *ia_gen;
	SSL *ssl;
	char *ssl_readbuf;
	int conn_fd;
	struct bsock *bsock;
	struct ppd_bsock_io_ssl_ctx bsock_ctx;

	void *m_ctx;
	uint64_t next_send;
	std::list<struct dsmbr_request_record *> req_in_flight;
};

struct dsmbr_slave {
	int conn_fd;
	/* stats */
	uint64_t time;
	uint64_t send_sz;
	uint64_t recv_sz;
	uint64_t reqs;
};

struct dsmbr_options {
	int verbose;
	char server_ip[64];
	int server_port;
	int conn_per_thread;
	int target_qps;
	int depth;
	int warmup;
	int duration;
	char ia_dist[128];
	char output_file[128];
	cpuset_t cpuset;
	char module_path[128];
	char *mod_argk[MAX_MOD_ARGS];
	char *mod_argv[MAX_MOD_ARGS];
	int mod_argc;
	int enable_tls;
	int master_mode;
	int slave_mode;

	// master mode
	char slave_ips[MAX_SLAVES][64];
	int num_slaves;

	// global states
	std::atomic<int> state = STATE_WAITING;
	sem_t worker_init_sem;
	std::atomic<int> worker_init_comp = 0;
	SSL_CTX *ssl_ctx;
	ppd_mod_info *m_info;
	void *m_global_ctx;
};

static struct dsmbr_options options = { .verbose = 0,
	.server_ip = "127.0.0.1",
	.conn_per_thread = 1,
	.target_qps = 0,
	.depth = 1,
	.warmup = 0,
	.duration = 5,
	.ia_dist = "fb_ia",
	.output_file = "samples.txt",
	.cpuset = CPUSET_T_INITIALIZER(1),
	.module_path = { 0 },
	.mod_argc = 0,
	.enable_tls = 0,
	.master_mode = 0,
	.slave_mode = 0,
	.num_slaves = 0,
	.ssl_ctx = nullptr,
	.m_info = nullptr,
	.m_global_ctx = nullptr };

static void
dsmbr_dump_options()
{
	std::stringstream ss;
	ss << "Configuration:\n"
	   << "        server: " << options.server_ip << std::endl
	   << "        port: " << options.server_port << std::endl
	   << "        connections per thread: " << options.conn_per_thread << std::endl
	   << "        enable TLS: " << options.enable_tls << std::endl
	   << "        target qps: " << options.target_qps << std::endl
	   << "        number of threads: " << CPU_COUNT(&options.cpuset) << std::endl
	   << "        verbose: " << options.verbose << std::endl
	   << "        master mode: " << options.master_mode << std::endl
	   << "        slave mode:" << options.slave_mode << std::endl
	   << "        module: " << options.module_path << std::endl
	   << "        run time: " << options.duration << std::endl
	   << "        warmup time: " << options.warmup << std::endl
	   << "        interarrival dist: " << options.ia_dist << std::endl
	   << "        output file: " << options.output_file << std::endl
	   << "        depth: " << options.depth << std::endl
	   << "        slaves:";

	for (int i = 0; i < options.num_slaves; i++) {
		ss << " " << options.slave_ips[i];
	}

	ss << std::endl;
	V("%s", ss.str().c_str());
}

static SSL *
dsmbr_tls_handshake_client(int conn_fd)
{
	SSL *ssl;
	int r;

	ssl = SSL_new(options.ssl_ctx);
	if (ssl == NULL) {
		E("SSL_new() failed: %ld\n", ERR_get_error());
	}

	if (SSL_set_fd(ssl, conn_fd) == 0) {
		E("SSL_set_fd() failed: %ld\n", ERR_get_error());
	}

	if ((r = SSL_connect(ssl)) <= 0) {
		E("SSL_connect() failed: %ld\n", ERR_get_error());
	}

	return ssl;
}

static void
dsmbr_create_tls_context()
{
	SSL_CTX *ctx;

	ctx = SSL_CTX_new(TLS_client_method());
	if (!ctx) {
		E("SSL_CTX_new() failed: %ld\n", ERR_get_error());
	}

	SSL_CTX_set_min_proto_version(ctx, TLS1_2_VERSION);
	SSL_CTX_set_max_proto_version(ctx, TLS1_2_VERSION);

	options.ssl_ctx = ctx;
}

static struct dsmbr_conn *
dsmbr_conn_create(void *thrd_ctx)
{
	struct sockaddr_in server_addr;

	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(options.server_port);
	server_addr.sin_addr.s_addr = inet_addr(options.server_ip);

	int enable = 1;
	struct timeval tv = { .tv_sec = CTRL_TIMEOUT, .tv_usec = 0 };

	int conn_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (conn_fd == -1) {
		E("socket() error: %d\n", errno);
	}
	if (setsockopt(conn_fd, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof(tv)) != 0) {
		E("setsockopt() rcvtimeo: %d\n", errno);
	}
	if (setsockopt(conn_fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable)) != 0) {
		E("setsockopt() reuseaddr: %d\n", errno);
	}
	if (setsockopt(conn_fd, SOL_SOCKET, SO_REUSEPORT, &enable, sizeof(enable)) != 0) {
		E("setsockopt() reuseport: %d\n", errno);
	}
	if (setsockopt(conn_fd, IPPROTO_TCP, TCP_NODELAY, &enable, sizeof(enable)) != 0) {
		E("setsockopt() nodelay: %d\n", errno);
	}
	if (connect(conn_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) != 0) {
		E("connect() failed: %d\n", errno);
	}

	V("Established client connection %d...\n", conn_fd);
	struct dsmbr_conn *conn = new struct dsmbr_conn;
	conn->conn_fd = conn_fd;
	struct bsock_ringbuf_io io;
	void *bsock_ctx = nullptr;
	if (options.enable_tls) {
		V("Initiating TLS handshake on connection %d...\n", conn_fd);
		conn->ssl = dsmbr_tls_handshake_client(conn_fd);
		io = ppd_bsock_io_ssl();
		conn->ssl_readbuf = new char[BSOCK_BUF_SZ];
		conn->bsock_ctx.ssl_readbuf = conn->ssl_readbuf;
		conn->bsock_ctx.ssl_readbuf_len = BSOCK_BUF_SZ;
		conn->bsock_ctx.ssl = conn->ssl;
		bsock_ctx = &conn->bsock_ctx;
	} else {
		io = bsock_io_posix();
		conn->ssl_readbuf = nullptr;
		conn->ssl = nullptr;
		bsock_ctx = (void *)(uintptr_t)conn_fd;
	}

	conn->bsock = bsock_create(bsock_ctx, &io, BSOCK_BUF_SZ, 0);

	conn->ia_gen = createGenerator(options.ia_dist);
	if (conn->ia_gen == NULL) {
		E("Failed to create generator \"%s\"\n", options.ia_dist);
	}
	conn->ia_gen->set_lambda((double)options.target_qps /
	    (double)(options.conn_per_thread * CPU_COUNT(&options.cpuset)));

	int status;
	if ((status = options.m_info->conn_init_cb(options.m_global_ctx, thrd_ctx, &conn->m_ctx)) !=
	    0) {
		E("Failed to create conn m_ctx: %d\n", status);
	}

	conn->next_send = 0;
	return conn;
}

static void
dsmbr_conn_free(struct dsmbr_conn *conn, void *thrd_ctx)
{
	if (conn->ssl != nullptr) {
		SSL_shutdown(conn->ssl);
		SSL_free(conn->ssl);
		delete[] conn->ssl_readbuf;
	}
	options.m_info->conn_free_cb(options.m_global_ctx, thrd_ctx, conn->m_ctx);

	bsock_free(conn->bsock);
	close(conn->conn_fd);
	delete conn->ia_gen;
	delete conn;
}

void *
dsmbr_worker_main(void *ctx)
{
	struct dsmbr_thread_ctx *tinfo = (struct dsmbr_thread_ctx *)ctx;
	struct timespec timesp = { .tv_sec = 0, .tv_nsec = 0 };
	struct kevent kevs[NEVENT];
	std::vector<struct dsmbr_conn *> conns;

	sem_wait(&options.worker_init_sem);
	V("Thread %d initializing...\n", tinfo->tid);
	int kqfd = kqueue();
	if (kqfd < 0) {
		E("Thread %d kqueue() failed: %d\n", tinfo->tid, errno);
	}
	struct ppd_msg *mbuf = (struct ppd_msg *)new char[PPD_MSG_MAX_SZ];

	void *m_ctx;
	if (options.m_info->thread_init_cb(tinfo->core, options.m_global_ctx, &m_ctx) != 0) {
		E("thread_create_cb() failed: %d\n", errno);
	}

	for (int i = 0; i < options.conn_per_thread; i++) {
		struct dsmbr_conn *conn = dsmbr_conn_create(m_ctx);
		conns.push_back(conn);

		struct kevent kev;
		EV_SET(&kev, conn->conn_fd, EVFILT_READ, EV_ADD, 0, 0, conn);
		if (kevent(kqfd, &kev, 1, NULL, 0, NULL) == -1) {
			E("kevent() failed: %d\n", errno);
		}
	}
	options.worker_init_comp.fetch_add(1, std::memory_order_relaxed);
	sem_post(&options.worker_init_sem);

	// create connections
	V("Thread %d waiting...\n", tinfo->tid);
	while (options.state.load(std::memory_order_relaxed) == STATE_WAITING) {
	};
	for (struct dsmbr_conn *conn : conns) {
		conn->next_send = get_time_us();
	}

	V("Thread %d starting...\n", tinfo->tid);
	while (true) {
		int ret = 0;

		if (options.state.load(std::memory_order_relaxed) == STATE_STOP) {
			break;
		}

		// read resp first if possible
		if ((ret = kevent(kqfd, NULL, 0, kevs, NEVENT, &timesp)) < 0) {
			E("Thread %d kevent() error %d.\n", tinfo->tid, errno);
		}

		int size = ret;
		for (int i = 0; i < size; i++) {
			struct dsmbr_conn *conn = (struct dsmbr_conn *)kevs[i].udata;
			if (kevs[i].flags & EV_EOF) {
				E("Thread %d connection %d EV_EOF ERR: %d.\n", tinfo->tid,
				    conn->conn_fd, kevs[i].fflags);
			}
			ret = bsock_poll(conn->bsock);
			if (ret < 0) {
				E("Thread %d connection %d bsock_poll() ERR %d.\n", tinfo->tid,
				    conn->conn_fd, ret);
			}
		}

		uint64_t cur_ts = get_time_us();
		for (struct dsmbr_conn *conn : conns) {
			while (true) {
				// read as many messages as possible
				ret = ppd_readmsg(conn->bsock, (char *)mbuf, PPD_MSG_MAX_SZ);
				if (ret == 0) {
					size_t recv_size = mbuf->size + PPD_MSG_HDR_SZ;
					ret = options.m_info->conn_recv_cb(mbuf->data, mbuf->size,
					    options.m_global_ctx, m_ctx, conn->m_ctx);
					if (ret != 0) {
						E("Thread %d connection %d conn_recv_cb() failed ERR %d.\n",
						    tinfo->tid, conn->conn_fd, errno);
					}
					struct dsmbr_request_record *rec =
					    conn->req_in_flight.front();
					conn->req_in_flight.pop_front();
					rec->recv_size = recv_size;
					rec->recv_ts = cur_ts;
					tinfo->stats.push_back(rec);
					D("Thread %d connection %d RECV msg of size %u latency %lu\n",
					    tinfo->tid, conn->conn_fd, mbuf->size,
					    rec->recv_ts - rec->send_ts);
				} else {
					if (errno == ENODATA) {
						// not enough data for next msg
						break;
					} else {
						E("ppd_readmsg failed with err %d\n", errno);
					}
				}
			}

			if (conn->next_send <= cur_ts &&
			    conn->req_in_flight.size() < (unsigned int)options.depth) {
				// send
				size_t out_sz;
				ret = options.m_info->conn_send_cb(mbuf->data, PPD_MSG_MAX_DATA_SZ,
				    &out_sz, options.m_global_ctx, m_ctx, conn->m_ctx);
				if (ret != 0) {
					E("Thread %d connection %d conn_send_cb() failed ERR %d.\n",
					    tinfo->tid, conn->conn_fd, errno);
				}

				mbuf->size = out_sz;

				struct dsmbr_request_record *rec = new struct dsmbr_request_record;
				rec->send_size = mbuf->size + sizeof(struct ppd_msg);
				rec->send_ts = get_time_us();

				// no blocking, always flush
				ret = ppd_writemsg(conn->bsock, mbuf);
				if (ret != 0) {
					E("Thread %d connection %d ppd_writemsg() failed ERR %d.\n",
					    tinfo->tid, conn->conn_fd, errno);
				}

				conn->req_in_flight.push_back(rec);
				conn->next_send += (uint64_t)(conn->ia_gen->generate() *
				    (double)S2US);
				D("Thread %d connection %d SEND msg of size %lu\n", tinfo->tid,
				    conn->conn_fd, out_sz);
			}
		}
	}

	V("Thread %d exiting...\n", tinfo->tid);
	close(kqfd);
	delete[] mbuf;

	for (unsigned int i = 0; i < conns.size(); i++) {
		dsmbr_conn_free(conns.at(i), m_ctx);
	}

	options.m_info->thread_free_cb(tinfo->core, options.m_global_ctx, m_ctx);
	return NULL;
}

static void
dsmbr_free_worker(struct dsmbr_thread_ctx *worker)
{
	for (auto stat : worker->stats) {
		delete stat;
	}
	delete worker;
}

static struct dsmbr_thread_ctx *
dsmbr_create_worker(int tid, int core)
{
	struct dsmbr_thread_ctx *tinfo = new struct dsmbr_thread_ctx;
	tinfo->tid = tid;
	tinfo->core = core;

	pthread_attr_t attr;
	int status;
	if ((status = pthread_attr_init(&attr)) != 0) {
		E("pthread_attr_init() failed: %d\n", status);
	}

	cpuset_t cpuset;
	CPU_ZERO(&cpuset);
	CPU_SET(core, &cpuset);

	status = pthread_attr_setaffinity_np(&attr, sizeof(cpuset), &cpuset);
	if (status != 0) {
		E("pthread_attr_setaffinity_np() failed : %d\n", status);
	}

	status = pthread_create(&tinfo->thrd, &attr, dsmbr_worker_main, tinfo);
	if (status != 0) {
		E("pthread_create() failed: %d\n", status);
	}

	return tinfo;
}

static void
dsmbr_master_connect_slaves(struct dsmbr_slave *slaves)
{
	/* create a connection to the clients */
	for (int i = 0; i < options.num_slaves; i++) {
		struct sockaddr_in csock_addr;
		int c_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
		csock_addr.sin_family = AF_INET;
		csock_addr.sin_addr.s_addr = inet_addr(options.slave_ips[i]);
		csock_addr.sin_port = htons(CTRL_PORT);

		V("Connecting to slave %s...\n", options.slave_ips[i]);

		if (connect(c_fd, (struct sockaddr *)&csock_addr, sizeof(csock_addr)) != 0) {
			E("Connect failed. ERR %d\n", errno);
		}
		slaves[i].conn_fd = c_fd;
	}
}

static int
dsmbr_slave_ctrl_sock_create(void)
{
	struct sockaddr_in server_addr;
	int status;
	const int enable = 1;
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(CTRL_PORT);
	server_addr.sin_addr.s_addr = INADDR_ANY;

	int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (fd < 0) {
		E("socket() returned %d\n", errno);
	}

	if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &enable, sizeof(enable)) < 0) {
		E("setsockopt() NODELAY %d\n", errno);
	}

	status = bind(fd, (struct sockaddr *)&server_addr, sizeof(server_addr));
	if (status < 0) {
		E("bind() returned %d\n", errno);
	}

	status = listen(fd, CTRL_BACKLOG);
	if (status < 0) {
		E("listen() returned %d\n", errno);
	}

	return fd;
}

static void
usage()
{
	fprintf(stdout,
	    "Options:\n"
	    "    -q: target qps.\n"
	    "    -s: server addr.\n"
	    "    -p: server port.\n"
	    "    -o: output file path.\n"
	    "    -a: worker thread cpulist.\n"
	    "    -c: connections per thread.\n"
	    "    -m: module path.\n"
	    "    -M: slave ips, repeatable, enables master mode.\n"
	    "    -S: slave mode.\n"
	    "    -v: verbose mode.\n"
	    "    -t: run time.\n"
	    "    -T: warmup time.\n"
	    "    -i: interarrival time distribution.\n"
	    "    -O: module arguments ('key'='value'), repeatable.\n\n");
}

static int
dsmbr_slave_accept_master(int slave_ctrl_sock)
{
	int ret;
	int conn_fd;
	struct sockaddr addr;
	socklen_t addrlen;

	ret = accept(slave_ctrl_sock, &addr, &addrlen);
	if (ret < 0) {
		E("Failed to accept master connection: %d\n", errno);
	}
	conn_fd = ret;

	V("Accepted master connection %d.\n", conn_fd);

	return conn_fd;
}

static void
dsmbr_getopt(int argc, char *argv[])
{
	char ch;
	while ((ch = getopt(argc, argv, "q:s:p:o:a:c:m:M:Svt:T:i:O:h")) != -1) {
		switch (ch) {
		case 'q': {
			options.target_qps = strtoul(optarg, NULL, 10);
			break;
		}
		case 's': {
			if (nslookup(optarg, options.server_ip, sizeof(options.server_ip)) != 0) {
				E("nslookup failed with %d for %s\n", errno, optarg);
			}
			break;
		}
		case 'p': {
			options.server_port = strtoul(optarg, NULL, 10);
			break;
		}
		case 'o': {
			strncpy(options.output_file, optarg, sizeof(options.output_file));
			break;
		}
		case 'a': {
			cpulist_to_cpuset(optarg, &options.cpuset);
			break;
		}
		case 'c': {
			options.conn_per_thread = strtoul(optarg, NULL, 10);
			break;
		}
		case 'm': {
			strncpy(options.module_path, optarg, sizeof(options.module_path));
			break;
		}
		case 'M': {
			options.master_mode = 1;
			if (nslookup(optarg, options.slave_ips[options.num_slaves],
				sizeof(options.slave_ips[0])) != 0) {
				E("nslookup failed with %d for %s\n", errno, optarg);
			}
			options.num_slaves++;
			if (options.num_slaves > MAX_SLAVES) {
				E("Too many slaves: %d > %d\n", options.num_slaves, MAX_SLAVES);
			}
			break;
		}
		case 'S': {
			options.slave_mode = 1;
			break;
		}
		case 'v': {
			options.verbose++;
			if (options.verbose == INFO_VERBOSITY) {
				W("Verbose mode may cause SUBSTANTIAL latency fluctuation in some terminals emulators\n");
			} else if (options.verbose == DEBUG_VERBOSITY) {
				W("Debug mode enabled. Expect very verbose output.\n");
			}
			logger_set_verbosity(options.verbose);
			break;
		}
		case 't': {
			options.duration = strtoul(optarg, NULL, 10);
			break;
		}
		case 'T': {
			options.warmup = strtoul(optarg, NULL, 10);
			break;
		}
		case 'i': {
			strncpy(options.ia_dist, optarg, sizeof(options.ia_dist));
			break;
		}
		case 'O': {
			options.mod_argk[options.mod_argc] = new char[MAX_MOD_ARG_LEN];
			options.mod_argv[options.mod_argc] = new char[MAX_MOD_ARG_LEN];
			split_kvstr(optarg, "=", options.mod_argk[options.mod_argc],
			    MAX_MOD_ARG_LEN, options.mod_argv[options.mod_argc], MAX_MOD_ARG_LEN);
			options.mod_argc++;
			break;
		}
		case 'h':
			usage();
			exit(0);
		default:
			E("Unrecognized option -%c\n\n", ch);
		}
	}
}

static void
dsmbr_send_ctrl_code(int sock, uint32_t code)
{
	int ret;
	struct dsmbr_ctrl_msg msg;
	msg.code = code;
	ret = dsmbr_send_ctrl_msg(sock, &msg);
	if (ret != 0) {
		E("Failed to send ctrl message %d\n", errno);
	}
	return;
}

static void
dsmbr_wait_ctrl_code(int sock, uint32_t code)
{
	int ret;
	struct dsmbr_ctrl_msg msg;
	ret = dsmbr_recv_ctrl_msg(sock, &msg);
	if (ret != 0) {
		E("Failed to recv ctrl message %d\n", errno);
	}
	if (msg.code != code) {
		E("Unexpected message code 0x%x, expected 0x%x\n", msg.code, code);
	}
	return;
}

/*
 * protocol:
 *
 * master -> client SYNC
 * client and master all establish connections to the server
 * client -> master ACK
 * master -> client START
 * master RUNS for X seconds, client runs forever
 * master -> client STOP
 * client -> master STAT
 */
int
main(int argc, char *argv[])
{
	dsmbr_getopt(argc, argv);
	dsmbr_dump_options();

	dsmbr_create_tls_context();

	if (sem_init(&options.worker_init_sem, 0, THRD_INIT_PARALLEL) != 0) {
		E("sem_init failed: %d\n", errno);
	}

	V("Loading module %s...\n", options.module_path);
	options.m_info = ppd_load_module(options.module_path);
	V("Loaded module \"%s\".\n", options.m_info->name);

	V("Initializing module...\n");
	options.m_info->global_init_cb(options.mod_argc, options.mod_argk, options.mod_argv,
	    &options.m_global_ctx);

	FILE *resp_fp_csv = NULL;
	if (!options.slave_mode) {
		resp_fp_csv = fopen(options.output_file, "w");
		if (resp_fp_csv == NULL) {
			E("Cannot open file %s for writing %d.", options.output_file, errno);
			exit(1);
		}
	}

	struct dsmbr_slave slaves[MAX_SLAVES];
	int ret;
	int slave_ctrl_sock = -1;
	int master_ctrl_conn = -1;
	std::vector<struct dsmbr_thread_ctx *> workers;
	uint64_t start_ts;
	uint64_t end_ts;
	uint64_t warmup_ts;
	struct dsmbr_ctrl_msg ctrl_msg;
	int kqfd = kqueue();
	if (kqfd < 0) {
		E("kqueue() failed with %d\n", errno);
	}

	if (options.master_mode) {
		/* initiate connections to clients */
		V("M: connecting to slaves.\n");
		dsmbr_master_connect_slaves(slaves);
		V("M: SYNC to slaves.\n");
		for (int i = 0; i < options.num_slaves; i++) {
			dsmbr_send_ctrl_code(slaves[i].conn_fd, CTRL_SYNC);
		}
	} else if (options.slave_mode) {
		slave_ctrl_sock = dsmbr_slave_ctrl_sock_create();
		V("S: waiting for master connection...\n");
		master_ctrl_conn = dsmbr_slave_accept_master(slave_ctrl_sock);
		// add to kqueue
		V("S: waiting for master SYNC %d...\n", master_ctrl_conn);
		dsmbr_wait_ctrl_code(master_ctrl_conn, CTRL_SYNC);

		struct kevent kev;
		EV_SET(&kev, master_ctrl_conn, EVFILT_READ, EV_ADD, 0, 0, NULL);
		if (kevent(kqfd, &kev, 1, NULL, 0, NULL) == -1) {
			E("kevent() failed: %d\n", errno);
		}
	}

	// here slaves and master are on the same page */
	int core;
	int tid = 0;
	CPU_FOREACH_ISSET (core, &options.cpuset) {
		workers.push_back(dsmbr_create_worker(tid, core));
		V("Created thread %d on core %d.\n", tid, core);
		tid++;
	}

	V("Waiting for worker threads connection establishment.\n");
	while (options.worker_init_comp.load(std::memory_order_relaxed) !=
	    CPU_COUNT(&options.cpuset)) {
	};

	// now all connections are established
	if (options.master_mode) {
		V("M: waiting for slaves ACK...\n");
		for (int i = 0; i < options.num_slaves; i++) {
			dsmbr_wait_ctrl_code(slaves[i].conn_fd, CTRL_ACK);
		}
		V("M: START to slaves...\n");
		for (int i = 0; i < options.num_slaves; i++) {
			dsmbr_send_ctrl_code(slaves[i].conn_fd, CTRL_START);
		}
	} else if (options.slave_mode) {
		V("S: ACK to master...\n");
		dsmbr_send_ctrl_code(master_ctrl_conn, CTRL_ACK);
		V("S: waiting for master START...\n");
		dsmbr_wait_ctrl_code(master_ctrl_conn, CTRL_START);
	}

	V("Starting benchmark...\n");
	start_ts = get_time_us();
	warmup_ts = start_ts;
	// seq_cst to make sure start_ts happens before store
	options.state.store(STATE_RUN, std::memory_order_seq_cst);

	int cur_second = 0;
	struct kevent kev;
	if (!options.slave_mode) {
		// slave mode runs forever
		EV_SET(&kev, TIMER_MAGIC, EVFILT_TIMER, EV_ADD, NOTE_USECONDS, S2US, NULL);
		if (kevent(kqfd, &kev, 1, NULL, 0, NULL) == -1) {
			E("kevent() failed: %d\n", errno);
		}
	}
	while (true) {
		if (kevent(kqfd, NULL, 0, &kev, 1, NULL) == -1) {
			E("kevent() failed: %d\n", errno);
		}

		if (kev.ident == TIMER_MAGIC) {
			if (kev.data != 1) {
				E("Timer expired multiple times\n");
			}
			cur_second++;
			if ((int)cur_second == options.warmup) {
				warmup_ts = get_time_us();
			}
			if ((int)cur_second >= options.duration + options.warmup) {
				break;
			}
		} else if (options.slave_mode && (int)kev.ident == master_ctrl_conn) {
			dsmbr_wait_ctrl_code(master_ctrl_conn, CTRL_STOP);
			V("S: received STOP from master.\n");
			break;
		} else {
			E("Unknown kevent ident %d\n", (int)kev.ident);
		}
	}

	V("Stopping benchmark...\n");
	options.state.store(STATE_STOP, std::memory_order_seq_cst);
	end_ts = get_time_us();

	if (options.master_mode) {
		V("M: STOP to slaves...\n");
		for (int i = 0; i < options.num_slaves; i++) {
			dsmbr_send_ctrl_code(slaves[i].conn_fd, CTRL_STOP);
		}
	}

	// wait for thread exit
	for (unsigned int i = 0; i < workers.size(); i++) {
		if ((ret = pthread_join(workers.at(i)->thrd, NULL)) != 0) {
			E("pthread_join tid %d err %d\n", workers.at(i)->tid, ret);
		}
	}

	// obtain stats from threads
	uint64_t total_req = 0;
	uint64_t total_send = 0;
	uint64_t total_recv = 0;
	for (auto worker : workers) {
		for (auto stat : worker->stats) {
			total_req++;
			total_send += stat->send_size;
			total_recv += stat->recv_size;
		}
	}

	V("Reqs: %lu Time: %lu us Send: %lu bytes Recv: %lu bytes\n", total_req, end_ts - start_ts,
	    total_send, total_recv);

	if (options.master_mode) {
		V("M: waiting for slaves STAT...\n");
		for (int i = 0; i < options.num_slaves; i++) {
			if (dsmbr_recv_ctrl_msg(slaves[i].conn_fd, &ctrl_msg) != 0) {
				E("dsmbr_recv_ctrl_msg failed with %d.\n", errno);
			}
			if (ctrl_msg.code != CTRL_STAT) {
				E("Unexpected ctrl code %d, expected: %d.\n", ctrl_msg.code,
				    CTRL_STAT);
			}
			slaves[i].reqs = ctrl_msg.data[0];
			slaves[i].time = ctrl_msg.data[1];
			slaves[i].send_sz = ctrl_msg.data[2];
			slaves[i].recv_sz = ctrl_msg.data[3];
			V("M: received stats - Reqs: %lu Time: %lu us Send: %lu bytes Recv: %lu bytes\n",
			    slaves[i].reqs, slaves[i].time, slaves[i].send_sz, slaves[i].recv_sz);
		}
	} else if (options.slave_mode) {
		V("M: STAT to master...\n");
		ctrl_msg.code = CTRL_STAT;
		ctrl_msg.data[0] = total_req;
		ctrl_msg.data[1] = end_ts - start_ts;
		ctrl_msg.data[2] = total_send;
		ctrl_msg.data[3] = total_recv;
		if (dsmbr_send_ctrl_msg(master_ctrl_conn, &ctrl_msg) != 0) {
			E("dsmbr_send_ctrl_msg failed with %d.\n", errno);
		}
	}

	if (!options.slave_mode) {
		V("Saving results to %s ...\n", options.output_file);
		for (int i = 0; i < options.num_slaves; i++) {
			fprintf(resp_fp_csv, "S,%lu,%lu,%lu,%lu\n", slaves[i].reqs, slaves[i].time,
			    slaves[i].send_sz, slaves[i].recv_sz);
		}
		fprintf(resp_fp_csv, "M,%lu,%lu,%lu,%lu\n", total_req, end_ts - start_ts,
		    total_send, total_recv);
		for (auto worker : workers) {
			for (auto stat : worker->stats) {
				if (stat->send_ts < warmup_ts) {
					fprintf(resp_fp_csv, "W,%lu,%lu,%lu,%lu\n", stat->send_ts,
					    stat->recv_ts, stat->send_size, stat->recv_size);
				} else {
					fprintf(resp_fp_csv, "R,%lu,%lu,%lu,%lu\n", stat->send_ts,
					    stat->recv_ts, stat->send_size, stat->recv_size);
				}
			}
		}
		fflush(resp_fp_csv);
	}

	// clean up
	if (resp_fp_csv != NULL) {
		fclose(resp_fp_csv);
	}
	sem_destroy(&options.worker_init_sem);
	close(kqfd);
	if (slave_ctrl_sock != -1) {
		close(slave_ctrl_sock);
	}
	if (master_ctrl_conn != -1) {
		close(master_ctrl_conn);
	}
	for (int i = 0; i < options.num_slaves; i++) {
		close(slaves[i].conn_fd);
	}
	for (auto worker : workers) {
		dsmbr_free_worker(worker);
	}
	options.m_info->global_free_cb(options.m_global_ctx);
	for (int i = 0; i < options.mod_argc; i++) {
		delete[] options.mod_argk[i];
		delete[] options.mod_argv[i];
	}
	return 0;
}