linux/tools/testing/selftests/net/tcp_mmap.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright 2018 Google Inc.
   4 * Author: Eric Dumazet (edumazet@google.com)
   5 *
   6 * Reference program demonstrating tcp mmap() usage,
   7 * and SO_RCVLOWAT hints for receiver.
   8 *
   9 * Note : NIC with header split is needed to use mmap() on TCP :
  10 * Each incoming frame must be a multiple of PAGE_SIZE bytes of TCP payload.
  11 *
  12 * How to use on loopback interface :
  13 *
  14 *  ifconfig lo mtu 61512  # 15*4096 + 40 (ipv6 header) + 32 (TCP with TS option header)
  15 *  tcp_mmap -s -z &
  16 *  tcp_mmap -H ::1 -z
  17 *
  18 *  Or leave default lo mtu, but use -M option to set TCP_MAXSEG option to (4096 + 12)
  19 *      (4096 : page size on x86, 12: TCP TS option length)
  20 *  tcp_mmap -s -z -M $((4096+12)) &
  21 *  tcp_mmap -H ::1 -z -M $((4096+12))
  22 *
  23 * Note: -z option on sender uses MSG_ZEROCOPY, which forces a copy when packets go through loopback interface.
  24 *       We might use sendfile() instead, but really this test program is about mmap(), for receivers ;)
  25 *
  26 * $ ./tcp_mmap -s &                                 # Without mmap()
  27 * $ for i in {1..4}; do ./tcp_mmap -H ::1 -z ; done
  28 * received 32768 MB (0 % mmap'ed) in 14.1157 s, 19.4732 Gbit
  29 *   cpu usage user:0.057 sys:7.815, 240.234 usec per MB, 65531 c-switches
  30 * received 32768 MB (0 % mmap'ed) in 14.6833 s, 18.7204 Gbit
  31 *  cpu usage user:0.043 sys:8.103, 248.596 usec per MB, 65524 c-switches
  32 * received 32768 MB (0 % mmap'ed) in 11.143 s, 24.6682 Gbit
  33 *   cpu usage user:0.044 sys:6.576, 202.026 usec per MB, 65519 c-switches
  34 * received 32768 MB (0 % mmap'ed) in 14.9056 s, 18.4413 Gbit
  35 *   cpu usage user:0.036 sys:8.193, 251.129 usec per MB, 65530 c-switches
  36 * $ kill %1   # kill tcp_mmap server
  37 *
  38 * $ ./tcp_mmap -s -z &                              # With mmap()
  39 * $ for i in {1..4}; do ./tcp_mmap -H ::1 -z ; done
  40 * received 32768 MB (99.9939 % mmap'ed) in 6.73792 s, 40.7956 Gbit
  41 *   cpu usage user:0.045 sys:2.827, 87.6465 usec per MB, 65532 c-switches
  42 * received 32768 MB (99.9939 % mmap'ed) in 7.26732 s, 37.8238 Gbit
  43 *   cpu usage user:0.037 sys:3.087, 95.3369 usec per MB, 65532 c-switches
  44 * received 32768 MB (99.9939 % mmap'ed) in 7.61661 s, 36.0893 Gbit
  45 *   cpu usage user:0.046 sys:3.559, 110.016 usec per MB, 65529 c-switches
  46 * received 32768 MB (99.9939 % mmap'ed) in 7.43764 s, 36.9577 Gbit
  47 *   cpu usage user:0.035 sys:3.467, 106.873 usec per MB, 65530 c-switches
  48 */
  49#define _GNU_SOURCE
  50#include <pthread.h>
  51#include <sys/types.h>
  52#include <fcntl.h>
  53#include <error.h>
  54#include <sys/socket.h>
  55#include <sys/mman.h>
  56#include <sys/resource.h>
  57#include <unistd.h>
  58#include <string.h>
  59#include <stdlib.h>
  60#include <stdio.h>
  61#include <errno.h>
  62#include <time.h>
  63#include <sys/time.h>
  64#include <netinet/in.h>
  65#include <arpa/inet.h>
  66#include <poll.h>
  67#include <linux/tcp.h>
  68#include <assert.h>
  69
  70#ifndef MSG_ZEROCOPY
  71#define MSG_ZEROCOPY    0x4000000
  72#endif
  73
  74#define FILE_SZ (1UL << 35)
  75static int cfg_family = AF_INET6;
  76static socklen_t cfg_alen = sizeof(struct sockaddr_in6);
  77static int cfg_port = 8787;
  78
  79static int rcvbuf; /* Default: autotuning.  Can be set with -r <integer> option */
  80static int sndbuf; /* Default: autotuning.  Can be set with -w <integer> option */
  81static int zflg; /* zero copy option. (MSG_ZEROCOPY for sender, mmap() for receiver */
  82static int xflg; /* hash received data (simple xor) (-h option) */
  83static int keepflag; /* -k option: receiver shall keep all received file in memory (no munmap() calls) */
  84
  85static int chunk_size  = 512*1024;
  86
  87unsigned long htotal;
  88
  89static inline void prefetch(const void *x)
  90{
  91#if defined(__x86_64__)
  92        asm volatile("prefetcht0 %P0" : : "m" (*(const char *)x));
  93#endif
  94}
  95
  96void hash_zone(void *zone, unsigned int length)
  97{
  98        unsigned long temp = htotal;
  99
 100        while (length >= 8*sizeof(long)) {
 101                prefetch(zone + 384);
 102                temp ^= *(unsigned long *)zone;
 103                temp ^= *(unsigned long *)(zone + sizeof(long));
 104                temp ^= *(unsigned long *)(zone + 2*sizeof(long));
 105                temp ^= *(unsigned long *)(zone + 3*sizeof(long));
 106                temp ^= *(unsigned long *)(zone + 4*sizeof(long));
 107                temp ^= *(unsigned long *)(zone + 5*sizeof(long));
 108                temp ^= *(unsigned long *)(zone + 6*sizeof(long));
 109                temp ^= *(unsigned long *)(zone + 7*sizeof(long));
 110                zone += 8*sizeof(long);
 111                length -= 8*sizeof(long);
 112        }
 113        while (length >= 1) {
 114                temp ^= *(unsigned char *)zone;
 115                zone += 1;
 116                length--;
 117        }
 118        htotal = temp;
 119}
 120
 121void *child_thread(void *arg)
 122{
 123        unsigned long total_mmap = 0, total = 0;
 124        struct tcp_zerocopy_receive zc;
 125        unsigned long delta_usec;
 126        int flags = MAP_SHARED;
 127        struct timeval t0, t1;
 128        char *buffer = NULL;
 129        void *addr = NULL;
 130        double throughput;
 131        struct rusage ru;
 132        int lu, fd;
 133
 134        fd = (int)(unsigned long)arg;
 135
 136        gettimeofday(&t0, NULL);
 137
 138        fcntl(fd, F_SETFL, O_NDELAY);
 139        buffer = malloc(chunk_size);
 140        if (!buffer) {
 141                perror("malloc");
 142                goto error;
 143        }
 144        if (zflg) {
 145                addr = mmap(NULL, chunk_size, PROT_READ, flags, fd, 0);
 146                if (addr == (void *)-1)
 147                        zflg = 0;
 148        }
 149        while (1) {
 150                struct pollfd pfd = { .fd = fd, .events = POLLIN, };
 151                int sub;
 152
 153                poll(&pfd, 1, 10000);
 154                if (zflg) {
 155                        socklen_t zc_len = sizeof(zc);
 156                        int res;
 157
 158                        zc.address = (__u64)addr;
 159                        zc.length = chunk_size;
 160                        zc.recv_skip_hint = 0;
 161                        res = getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE,
 162                                         &zc, &zc_len);
 163                        if (res == -1)
 164                                break;
 165
 166                        if (zc.length) {
 167                                assert(zc.length <= chunk_size);
 168                                total_mmap += zc.length;
 169                                if (xflg)
 170                                        hash_zone(addr, zc.length);
 171                                total += zc.length;
 172                        }
 173                        if (zc.recv_skip_hint) {
 174                                assert(zc.recv_skip_hint <= chunk_size);
 175                                lu = read(fd, buffer, zc.recv_skip_hint);
 176                                if (lu > 0) {
 177                                        if (xflg)
 178                                                hash_zone(buffer, lu);
 179                                        total += lu;
 180                                }
 181                        }
 182                        continue;
 183                }
 184                sub = 0;
 185                while (sub < chunk_size) {
 186                        lu = read(fd, buffer + sub, chunk_size - sub);
 187                        if (lu == 0)
 188                                goto end;
 189                        if (lu < 0)
 190                                break;
 191                        if (xflg)
 192                                hash_zone(buffer + sub, lu);
 193                        total += lu;
 194                        sub += lu;
 195                }
 196        }
 197end:
 198        gettimeofday(&t1, NULL);
 199        delta_usec = (t1.tv_sec - t0.tv_sec) * 1000000 + t1.tv_usec - t0.tv_usec;
 200
 201        throughput = 0;
 202        if (delta_usec)
 203                throughput = total * 8.0 / (double)delta_usec / 1000.0;
 204        getrusage(RUSAGE_THREAD, &ru);
 205        if (total > 1024*1024) {
 206                unsigned long total_usec;
 207                unsigned long mb = total >> 20;
 208                total_usec = 1000000*ru.ru_utime.tv_sec + ru.ru_utime.tv_usec +
 209                             1000000*ru.ru_stime.tv_sec + ru.ru_stime.tv_usec;
 210                printf("received %lg MB (%lg %% mmap'ed) in %lg s, %lg Gbit\n"
 211                       "  cpu usage user:%lg sys:%lg, %lg usec per MB, %lu c-switches\n",
 212                                total / (1024.0 * 1024.0),
 213                                100.0*total_mmap/total,
 214                                (double)delta_usec / 1000000.0,
 215                                throughput,
 216                                (double)ru.ru_utime.tv_sec + (double)ru.ru_utime.tv_usec / 1000000.0,
 217                                (double)ru.ru_stime.tv_sec + (double)ru.ru_stime.tv_usec / 1000000.0,
 218                                (double)total_usec/mb,
 219                                ru.ru_nvcsw);
 220        }
 221error:
 222        free(buffer);
 223        close(fd);
 224        if (zflg)
 225                munmap(addr, chunk_size);
 226        pthread_exit(0);
 227}
 228
 229static void apply_rcvsnd_buf(int fd)
 230{
 231        if (rcvbuf && setsockopt(fd, SOL_SOCKET,
 232                                 SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) == -1) {
 233                perror("setsockopt SO_RCVBUF");
 234        }
 235
 236        if (sndbuf && setsockopt(fd, SOL_SOCKET,
 237                                 SO_SNDBUF, &sndbuf, sizeof(sndbuf)) == -1) {
 238                perror("setsockopt SO_SNDBUF");
 239        }
 240}
 241
 242
 243static void setup_sockaddr(int domain, const char *str_addr,
 244                           struct sockaddr_storage *sockaddr)
 245{
 246        struct sockaddr_in6 *addr6 = (void *) sockaddr;
 247        struct sockaddr_in *addr4 = (void *) sockaddr;
 248
 249        switch (domain) {
 250        case PF_INET:
 251                memset(addr4, 0, sizeof(*addr4));
 252                addr4->sin_family = AF_INET;
 253                addr4->sin_port = htons(cfg_port);
 254                if (str_addr &&
 255                    inet_pton(AF_INET, str_addr, &(addr4->sin_addr)) != 1)
 256                        error(1, 0, "ipv4 parse error: %s", str_addr);
 257                break;
 258        case PF_INET6:
 259                memset(addr6, 0, sizeof(*addr6));
 260                addr6->sin6_family = AF_INET6;
 261                addr6->sin6_port = htons(cfg_port);
 262                if (str_addr &&
 263                    inet_pton(AF_INET6, str_addr, &(addr6->sin6_addr)) != 1)
 264                        error(1, 0, "ipv6 parse error: %s", str_addr);
 265                break;
 266        default:
 267                error(1, 0, "illegal domain");
 268        }
 269}
 270
 271static void do_accept(int fdlisten)
 272{
 273        if (setsockopt(fdlisten, SOL_SOCKET, SO_RCVLOWAT,
 274                       &chunk_size, sizeof(chunk_size)) == -1) {
 275                perror("setsockopt SO_RCVLOWAT");
 276        }
 277
 278        apply_rcvsnd_buf(fdlisten);
 279
 280        while (1) {
 281                struct sockaddr_in addr;
 282                socklen_t addrlen = sizeof(addr);
 283                pthread_t th;
 284                int fd, res;
 285
 286                fd = accept(fdlisten, (struct sockaddr *)&addr, &addrlen);
 287                if (fd == -1) {
 288                        perror("accept");
 289                        continue;
 290                }
 291                res = pthread_create(&th, NULL, child_thread,
 292                                     (void *)(unsigned long)fd);
 293                if (res) {
 294                        errno = res;
 295                        perror("pthread_create");
 296                        close(fd);
 297                }
 298        }
 299}
 300
 301int main(int argc, char *argv[])
 302{
 303        struct sockaddr_storage listenaddr, addr;
 304        unsigned int max_pacing_rate = 0;
 305        unsigned long total = 0;
 306        char *host = NULL;
 307        int fd, c, on = 1;
 308        char *buffer;
 309        int sflg = 0;
 310        int mss = 0;
 311
 312        while ((c = getopt(argc, argv, "46p:svr:w:H:zxkP:M:")) != -1) {
 313                switch (c) {
 314                case '4':
 315                        cfg_family = PF_INET;
 316                        cfg_alen = sizeof(struct sockaddr_in);
 317                        break;
 318                case '6':
 319                        cfg_family = PF_INET6;
 320                        cfg_alen = sizeof(struct sockaddr_in6);
 321                        break;
 322                case 'p':
 323                        cfg_port = atoi(optarg);
 324                        break;
 325                case 'H':
 326                        host = optarg;
 327                        break;
 328                case 's': /* server : listen for incoming connections */
 329                        sflg++;
 330                        break;
 331                case 'r':
 332                        rcvbuf = atoi(optarg);
 333                        break;
 334                case 'w':
 335                        sndbuf = atoi(optarg);
 336                        break;
 337                case 'z':
 338                        zflg = 1;
 339                        break;
 340                case 'M':
 341                        mss = atoi(optarg);
 342                        break;
 343                case 'x':
 344                        xflg = 1;
 345                        break;
 346                case 'k':
 347                        keepflag = 1;
 348                        break;
 349                case 'P':
 350                        max_pacing_rate = atoi(optarg) ;
 351                        break;
 352                default:
 353                        exit(1);
 354                }
 355        }
 356        if (sflg) {
 357                int fdlisten = socket(cfg_family, SOCK_STREAM, 0);
 358
 359                if (fdlisten == -1) {
 360                        perror("socket");
 361                        exit(1);
 362                }
 363                apply_rcvsnd_buf(fdlisten);
 364                setsockopt(fdlisten, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
 365
 366                setup_sockaddr(cfg_family, host, &listenaddr);
 367
 368                if (mss &&
 369                    setsockopt(fdlisten, IPPROTO_TCP, TCP_MAXSEG,
 370                               &mss, sizeof(mss)) == -1) {
 371                        perror("setsockopt TCP_MAXSEG");
 372                        exit(1);
 373                }
 374                if (bind(fdlisten, (const struct sockaddr *)&listenaddr, cfg_alen) == -1) {
 375                        perror("bind");
 376                        exit(1);
 377                }
 378                if (listen(fdlisten, 128) == -1) {
 379                        perror("listen");
 380                        exit(1);
 381                }
 382                do_accept(fdlisten);
 383        }
 384        buffer = mmap(NULL, chunk_size, PROT_READ | PROT_WRITE,
 385                              MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 386        if (buffer == (char *)-1) {
 387                perror("mmap");
 388                exit(1);
 389        }
 390
 391        fd = socket(cfg_family, SOCK_STREAM, 0);
 392        if (fd == -1) {
 393                perror("socket");
 394                exit(1);
 395        }
 396        apply_rcvsnd_buf(fd);
 397
 398        setup_sockaddr(cfg_family, host, &addr);
 399
 400        if (mss &&
 401            setsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) {
 402                perror("setsockopt TCP_MAXSEG");
 403                exit(1);
 404        }
 405        if (connect(fd, (const struct sockaddr *)&addr, cfg_alen) == -1) {
 406                perror("connect");
 407                exit(1);
 408        }
 409        if (max_pacing_rate &&
 410            setsockopt(fd, SOL_SOCKET, SO_MAX_PACING_RATE,
 411                       &max_pacing_rate, sizeof(max_pacing_rate)) == -1)
 412                perror("setsockopt SO_MAX_PACING_RATE");
 413
 414        if (zflg && setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY,
 415                               &on, sizeof(on)) == -1) {
 416                perror("setsockopt SO_ZEROCOPY, (-z option disabled)");
 417                zflg = 0;
 418        }
 419        while (total < FILE_SZ) {
 420                long wr = FILE_SZ - total;
 421
 422                if (wr > chunk_size)
 423                        wr = chunk_size;
 424                /* Note : we just want to fill the pipe with 0 bytes */
 425                wr = send(fd, buffer, wr, zflg ? MSG_ZEROCOPY : 0);
 426                if (wr <= 0)
 427                        break;
 428                total += wr;
 429        }
 430        close(fd);
 431        munmap(buffer, chunk_size);
 432        return 0;
 433}
 434