--- /dev/null
+/*
+ * Copyright 2018 Google Inc.
+ * Author: Eric Dumazet (edumazet@google.com)
+ *
+ * Reference program demonstrating tcp mmap() usage,
+ * and SO_RCVLOWAT hints for receiver.
+ *
+ * Note : NIC with header split is needed to use mmap() on TCP :
+ * Each incoming frame must be a multiple of PAGE_SIZE bytes of TCP payload.
+ *
+ * How to use on loopback interface :
+ *
+ * ifconfig lo mtu 61512 # 15*4096 + 40 (ipv6 header) + 32 (TCP with TS option header)
+ * tcp_mmap -s -z &
+ * tcp_mmap -H ::1 -z
+ *
+ * Or leave default lo mtu, but use -M option to set TCP_MAXSEG option to (4096 + 12)
+ * (4096 : page size on x86, 12: TCP TS option length)
+ * tcp_mmap -s -z -M $((4096+12)) &
+ * tcp_mmap -H ::1 -z -M $((4096+12))
+ *
+ * Note: -z option on sender uses MSG_ZEROCOPY, which forces a copy when packets go through loopback interface.
+ * We might use sendfile() instead, but really this test program is about mmap(), for receivers ;)
+ *
+ * $ ./tcp_mmap -s & # Without mmap()
+ * $ for i in {1..4}; do ./tcp_mmap -H ::1 -z ; done
+ * received 32768 MB (0 % mmap'ed) in 14.1157 s, 19.4732 Gbit
+ * cpu usage user:0.057 sys:7.815, 240.234 usec per MB, 65531 c-switches
+ * received 32768 MB (0 % mmap'ed) in 14.6833 s, 18.7204 Gbit
+ * cpu usage user:0.043 sys:8.103, 248.596 usec per MB, 65524 c-switches
+ * received 32768 MB (0 % mmap'ed) in 11.143 s, 24.6682 Gbit
+ * cpu usage user:0.044 sys:6.576, 202.026 usec per MB, 65519 c-switches
+ * received 32768 MB (0 % mmap'ed) in 14.9056 s, 18.4413 Gbit
+ * cpu usage user:0.036 sys:8.193, 251.129 usec per MB, 65530 c-switches
+ * $ kill %1 # kill tcp_mmap server
+ *
+ * $ ./tcp_mmap -s -z & # With mmap()
+ * $ for i in {1..4}; do ./tcp_mmap -H ::1 -z ; done
+ * received 32768 MB (99.9939 % mmap'ed) in 6.73792 s, 40.7956 Gbit
+ * cpu usage user:0.045 sys:2.827, 87.6465 usec per MB, 65532 c-switches
+ * received 32768 MB (99.9939 % mmap'ed) in 7.26732 s, 37.8238 Gbit
+ * cpu usage user:0.037 sys:3.087, 95.3369 usec per MB, 65532 c-switches
+ * received 32768 MB (99.9939 % mmap'ed) in 7.61661 s, 36.0893 Gbit
+ * cpu usage user:0.046 sys:3.559, 110.016 usec per MB, 65529 c-switches
+ * received 32768 MB (99.9939 % mmap'ed) in 7.43764 s, 36.9577 Gbit
+ * cpu usage user:0.035 sys:3.467, 106.873 usec per MB, 65530 c-switches
+ *
+ * License (GPLv2):
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#define _GNU_SOURCE
+#include <pthread.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <error.h>
+#include <sys/socket.h>
+#include <sys/mman.h>
+#include <sys/resource.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/time.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <arpa/inet.h>
+#include <poll.h>
+
+#ifndef MSG_ZEROCOPY
+#define MSG_ZEROCOPY 0x4000000
+#endif
+
+#define FILE_SZ (1UL << 35)
+static int cfg_family = AF_INET6;
+static socklen_t cfg_alen = sizeof(struct sockaddr_in6);
+static int cfg_port = 8787;
+
+static int rcvbuf; /* Default: autotuning. Can be set with -r <integer> option */
+static int sndbuf; /* Default: autotuning. Can be set with -w <integer> option */
+static int zflg; /* zero copy option. (MSG_ZEROCOPY for sender, mmap() for receiver */
+static int xflg; /* hash received data (simple xor) (-h option) */
+static int keepflag; /* -k option: receiver shall keep all received file in memory (no munmap() calls) */
+
+static int chunk_size = 512*1024;
+
+unsigned long htotal;
+
+static inline void prefetch(const void *x)
+{
+#if defined(__x86_64__)
+ asm volatile("prefetcht0 %P0" : : "m" (*(const char *)x));
+#endif
+}
+
+void hash_zone(void *zone, unsigned int length)
+{
+ unsigned long temp = htotal;
+
+ while (length >= 8*sizeof(long)) {
+ prefetch(zone + 384);
+ temp ^= *(unsigned long *)zone;
+ temp ^= *(unsigned long *)(zone + sizeof(long));
+ temp ^= *(unsigned long *)(zone + 2*sizeof(long));
+ temp ^= *(unsigned long *)(zone + 3*sizeof(long));
+ temp ^= *(unsigned long *)(zone + 4*sizeof(long));
+ temp ^= *(unsigned long *)(zone + 5*sizeof(long));
+ temp ^= *(unsigned long *)(zone + 6*sizeof(long));
+ temp ^= *(unsigned long *)(zone + 7*sizeof(long));
+ zone += 8*sizeof(long);
+ length -= 8*sizeof(long);
+ }
+ while (length >= 1) {
+ temp ^= *(unsigned char *)zone;
+ zone += 1;
+ length--;
+ }
+ htotal = temp;
+}
+
+void *child_thread(void *arg)
+{
+ unsigned long total_mmap = 0, total = 0;
+ unsigned long delta_usec;
+ int flags = MAP_SHARED;
+ struct timeval t0, t1;
+ char *buffer = NULL;
+ void *oaddr = NULL;
+ double throughput;
+ struct rusage ru;
+ int lu, fd;
+
+ fd = (int)(unsigned long)arg;
+
+ gettimeofday(&t0, NULL);
+
+ fcntl(fd, F_SETFL, O_NDELAY);
+ buffer = malloc(chunk_size);
+ if (!buffer) {
+ perror("malloc");
+ goto error;
+ }
+ while (1) {
+ struct pollfd pfd = { .fd = fd, .events = POLLIN, };
+ int sub;
+
+ poll(&pfd, 1, 10000);
+ if (zflg) {
+ void *naddr;
+
+ naddr = mmap(oaddr, chunk_size, PROT_READ, flags, fd, 0);
+ if (naddr == (void *)-1) {
+ if (errno == EAGAIN) {
+ /* That is if SO_RCVLOWAT is buggy */
+ usleep(1000);
+ continue;
+ }
+ if (errno == EINVAL) {
+ flags = MAP_SHARED;
+ oaddr = NULL;
+ goto fallback;
+ }
+ if (errno != EIO)
+ perror("mmap()");
+ break;
+ }
+ total_mmap += chunk_size;
+ if (xflg)
+ hash_zone(naddr, chunk_size);
+ total += chunk_size;
+ if (!keepflag) {
+ flags |= MAP_FIXED;
+ oaddr = naddr;
+ }
+ continue;
+ }
+fallback:
+ sub = 0;
+ while (sub < chunk_size) {
+ lu = read(fd, buffer + sub, chunk_size - sub);
+ if (lu == 0)
+ goto end;
+ if (lu < 0)
+ break;
+ if (xflg)
+ hash_zone(buffer + sub, lu);
+ total += lu;
+ sub += lu;
+ }
+ }
+end:
+ gettimeofday(&t1, NULL);
+ delta_usec = (t1.tv_sec - t0.tv_sec) * 1000000 + t1.tv_usec - t0.tv_usec;
+
+ throughput = 0;
+ if (delta_usec)
+ throughput = total * 8.0 / (double)delta_usec / 1000.0;
+ getrusage(RUSAGE_THREAD, &ru);
+ if (total > 1024*1024) {
+ unsigned long total_usec;
+ unsigned long mb = total >> 20;
+ total_usec = 1000000*ru.ru_utime.tv_sec + ru.ru_utime.tv_usec +
+ 1000000*ru.ru_stime.tv_sec + ru.ru_stime.tv_usec;
+ printf("received %lg MB (%lg %% mmap'ed) in %lg s, %lg Gbit\n"
+ " cpu usage user:%lg sys:%lg, %lg usec per MB, %lu c-switches\n",
+ total / (1024.0 * 1024.0),
+ 100.0*total_mmap/total,
+ (double)delta_usec / 1000000.0,
+ throughput,
+ (double)ru.ru_utime.tv_sec + (double)ru.ru_utime.tv_usec / 1000000.0,
+ (double)ru.ru_stime.tv_sec + (double)ru.ru_stime.tv_usec / 1000000.0,
+ (double)total_usec/mb,
+ ru.ru_nvcsw);
+ }
+error:
+ free(buffer);
+ close(fd);
+ pthread_exit(0);
+}
+
+static void apply_rcvsnd_buf(int fd)
+{
+ if (rcvbuf && setsockopt(fd, SOL_SOCKET,
+ SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) == -1) {
+ perror("setsockopt SO_RCVBUF");
+ }
+
+ if (sndbuf && setsockopt(fd, SOL_SOCKET,
+ SO_SNDBUF, &sndbuf, sizeof(sndbuf)) == -1) {
+ perror("setsockopt SO_SNDBUF");
+ }
+}
+
+
+static void setup_sockaddr(int domain, const char *str_addr,
+ struct sockaddr_storage *sockaddr)
+{
+ struct sockaddr_in6 *addr6 = (void *) sockaddr;
+ struct sockaddr_in *addr4 = (void *) sockaddr;
+
+ switch (domain) {
+ case PF_INET:
+ memset(addr4, 0, sizeof(*addr4));
+ addr4->sin_family = AF_INET;
+ addr4->sin_port = htons(cfg_port);
+ if (str_addr &&
+ inet_pton(AF_INET, str_addr, &(addr4->sin_addr)) != 1)
+ error(1, 0, "ipv4 parse error: %s", str_addr);
+ break;
+ case PF_INET6:
+ memset(addr6, 0, sizeof(*addr6));
+ addr6->sin6_family = AF_INET6;
+ addr6->sin6_port = htons(cfg_port);
+ if (str_addr &&
+ inet_pton(AF_INET6, str_addr, &(addr6->sin6_addr)) != 1)
+ error(1, 0, "ipv6 parse error: %s", str_addr);
+ break;
+ default:
+ error(1, 0, "illegal domain");
+ }
+}
+
+static void do_accept(int fdlisten)
+{
+ if (setsockopt(fdlisten, SOL_SOCKET, SO_RCVLOWAT,
+ &chunk_size, sizeof(chunk_size)) == -1) {
+ perror("setsockopt SO_RCVLOWAT");
+ }
+
+ apply_rcvsnd_buf(fdlisten);
+
+ while (1) {
+ struct sockaddr_in addr;
+ socklen_t addrlen = sizeof(addr);
+ pthread_t th;
+ int fd, res;
+
+ fd = accept(fdlisten, (struct sockaddr *)&addr, &addrlen);
+ if (fd == -1) {
+ perror("accept");
+ continue;
+ }
+ res = pthread_create(&th, NULL, child_thread,
+ (void *)(unsigned long)fd);
+ if (res) {
+ errno = res;
+ perror("pthread_create");
+ close(fd);
+ }
+ }
+}
+
+int main(int argc, char *argv[])
+{
+ struct sockaddr_storage listenaddr, addr;
+ unsigned int max_pacing_rate = 0;
+ unsigned long total = 0;
+ char *host = NULL;
+ int fd, c, on = 1;
+ char *buffer;
+ int sflg = 0;
+ int mss = 0;
+
+ while ((c = getopt(argc, argv, "46p:svr:w:H:zxkP:M:")) != -1) {
+ switch (c) {
+ case '4':
+ cfg_family = PF_INET;
+ cfg_alen = sizeof(struct sockaddr_in);
+ break;
+ case '6':
+ cfg_family = PF_INET6;
+ cfg_alen = sizeof(struct sockaddr_in6);
+ break;
+ case 'p':
+ cfg_port = atoi(optarg);
+ break;
+ case 'H':
+ host = optarg;
+ break;
+ case 's': /* server : listen for incoming connections */
+ sflg++;
+ break;
+ case 'r':
+ rcvbuf = atoi(optarg);
+ break;
+ case 'w':
+ sndbuf = atoi(optarg);
+ break;
+ case 'z':
+ zflg = 1;
+ break;
+ case 'M':
+ mss = atoi(optarg);
+ break;
+ case 'x':
+ xflg = 1;
+ break;
+ case 'k':
+ keepflag = 1;
+ break;
+ case 'P':
+ max_pacing_rate = atoi(optarg) ;
+ break;
+ default:
+ exit(1);
+ }
+ }
+ if (sflg) {
+ int fdlisten = socket(cfg_family, SOCK_STREAM, 0);
+
+ if (fdlisten == -1) {
+ perror("socket");
+ exit(1);
+ }
+ apply_rcvsnd_buf(fdlisten);
+ setsockopt(fdlisten, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+
+ setup_sockaddr(cfg_family, host, &listenaddr);
+
+ if (mss &&
+ setsockopt(fdlisten, SOL_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) {
+ perror("setsockopt TCP_MAXSEG");
+ exit(1);
+ }
+ if (bind(fdlisten, (const struct sockaddr *)&listenaddr, cfg_alen) == -1) {
+ perror("bind");
+ exit(1);
+ }
+ if (listen(fdlisten, 128) == -1) {
+ perror("listen");
+ exit(1);
+ }
+ do_accept(fdlisten);
+ }
+ buffer = mmap(NULL, chunk_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (buffer == (char *)-1) {
+ perror("mmap");
+ exit(1);
+ }
+
+ fd = socket(AF_INET6, SOCK_STREAM, 0);
+ if (fd == -1) {
+ perror("socket");
+ exit(1);
+ }
+ apply_rcvsnd_buf(fd);
+
+ setup_sockaddr(cfg_family, host, &addr);
+
+ if (mss &&
+ setsockopt(fd, SOL_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) {
+ perror("setsockopt TCP_MAXSEG");
+ exit(1);
+ }
+ if (connect(fd, (const struct sockaddr *)&addr, cfg_alen) == -1) {
+ perror("connect");
+ exit(1);
+ }
+ if (max_pacing_rate &&
+ setsockopt(fd, SOL_SOCKET, SO_MAX_PACING_RATE,
+ &max_pacing_rate, sizeof(max_pacing_rate)) == -1)
+ perror("setsockopt SO_MAX_PACING_RATE");
+
+ if (zflg && setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY,
+ &on, sizeof(on)) == -1) {
+ perror("setsockopt SO_ZEROCOPY, (-z option disabled)");
+ zflg = 0;
+ }
+ while (total < FILE_SZ) {
+ long wr = FILE_SZ - total;
+
+ if (wr > chunk_size)
+ wr = chunk_size;
+ /* Note : we just want to fill the pipe with 0 bytes */
+ wr = send(fd, buffer, wr, zflg ? MSG_ZEROCOPY : 0);
+ if (wr <= 0)
+ break;
+ total += wr;
+ }
+ close(fd);
+ munmap(buffer, chunk_size);
+ return 0;
+}