linux/tools/testing/selftests/net/tcp_mmap.c
<<
>>
Prefs
   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 (1ULL << 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 size_t chunk_size  = 512*1024;
  86
  87static size_t map_align;
  88
  89unsigned long htotal;
  90
  91static inline void prefetch(const void *x)
  92{
  93#if defined(__x86_64__)
  94        asm volatile("prefetcht0 %P0" : : "m" (*(const char *)x));
  95#endif
  96}
  97
  98void hash_zone(void *zone, unsigned int length)
  99{
 100        unsigned long temp = htotal;
 101
 102        while (length >= 8*sizeof(long)) {
 103                prefetch(zone + 384);
 104                temp ^= *(unsigned long *)zone;
 105                temp ^= *(unsigned long *)(zone + sizeof(long));
 106                temp ^= *(unsigned long *)(zone + 2*sizeof(long));
 107                temp ^= *(unsigned long *)(zone + 3*sizeof(long));
 108                temp ^= *(unsigned long *)(zone + 4*sizeof(long));
 109                temp ^= *(unsigned long *)(zone + 5*sizeof(long));
 110                temp ^= *(unsigned long *)(zone + 6*sizeof(long));
 111                temp ^= *(unsigned long *)(zone + 7*sizeof(long));
 112                zone += 8*sizeof(long);
 113                length -= 8*sizeof(long);
 114        }
 115        while (length >= 1) {
 116                temp ^= *(unsigned char *)zone;
 117                zone += 1;
 118                length--;
 119        }
 120        htotal = temp;
 121}
 122
 123#define ALIGN_UP(x, align_to)   (((x) + ((align_to)-1)) & ~((align_to)-1))
 124#define ALIGN_PTR_UP(p, ptr_align_to)   ((typeof(p))ALIGN_UP((unsigned long)(p), ptr_align_to))
 125
 126
 127static void *mmap_large_buffer(size_t need, size_t *allocated)
 128{
 129        void *buffer;
 130        size_t sz;
 131
 132        /* Attempt to use huge pages if possible. */
 133        sz = ALIGN_UP(need, map_align);
 134        buffer = mmap(NULL, sz, PROT_READ | PROT_WRITE,
 135                      MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);
 136
 137        if (buffer == (void *)-1) {
 138                sz = need;
 139                buffer = mmap(NULL, sz, PROT_READ | PROT_WRITE,
 140                              MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 141                if (buffer != (void *)-1)
 142                        fprintf(stderr, "MAP_HUGETLB attempt failed, look at /sys/kernel/mm/hugepages for optimal performance\n");
 143        }
 144        *allocated = sz;
 145        return buffer;
 146}
 147
 148void *child_thread(void *arg)
 149{
 150        unsigned long total_mmap = 0, total = 0;
 151        struct tcp_zerocopy_receive zc;
 152        unsigned long delta_usec;
 153        int flags = MAP_SHARED;
 154        struct timeval t0, t1;
 155        char *buffer = NULL;
 156        void *raddr = NULL;
 157        void *addr = NULL;
 158        double throughput;
 159        struct rusage ru;
 160        size_t buffer_sz;
 161        int lu, fd;
 162
 163        fd = (int)(unsigned long)arg;
 164
 165        gettimeofday(&t0, NULL);
 166
 167        fcntl(fd, F_SETFL, O_NDELAY);
 168        buffer = mmap_large_buffer(chunk_size, &buffer_sz);
 169        if (buffer == (void *)-1) {
 170                perror("mmap");
 171                goto error;
 172        }
 173        if (zflg) {
 174                raddr = mmap(NULL, chunk_size + map_align, PROT_READ, flags, fd, 0);
 175                if (raddr == (void *)-1) {
 176                        perror("mmap");
 177                        zflg = 0;
 178                } else {
 179                        addr = ALIGN_PTR_UP(raddr, map_align);
 180                }
 181        }
 182        while (1) {
 183                struct pollfd pfd = { .fd = fd, .events = POLLIN, };
 184                int sub;
 185
 186                poll(&pfd, 1, 10000);
 187                if (zflg) {
 188                        socklen_t zc_len = sizeof(zc);
 189                        int res;
 190
 191                        memset(&zc, 0, sizeof(zc));
 192                        zc.address = (__u64)((unsigned long)addr);
 193                        zc.length = chunk_size;
 194
 195                        res = getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE,
 196                                         &zc, &zc_len);
 197                        if (res == -1)
 198                                break;
 199
 200                        if (zc.length) {
 201                                assert(zc.length <= chunk_size);
 202                                total_mmap += zc.length;
 203                                if (xflg)
 204                                        hash_zone(addr, zc.length);
 205                                /* It is more efficient to unmap the pages right now,
 206                                 * instead of doing this in next TCP_ZEROCOPY_RECEIVE.
 207                                 */
 208                                madvise(addr, zc.length, MADV_DONTNEED);
 209                                total += zc.length;
 210                        }
 211                        if (zc.recv_skip_hint) {
 212                                assert(zc.recv_skip_hint <= chunk_size);
 213                                lu = read(fd, buffer, zc.recv_skip_hint);
 214                                if (lu > 0) {
 215                                        if (xflg)
 216                                                hash_zone(buffer, lu);
 217                                        total += lu;
 218                                }
 219                        }
 220                        continue;
 221                }
 222                sub = 0;
 223                while (sub < chunk_size) {
 224                        lu = read(fd, buffer + sub, chunk_size - sub);
 225                        if (lu == 0)
 226                                goto end;
 227                        if (lu < 0)
 228                                break;
 229                        if (xflg)
 230                                hash_zone(buffer + sub, lu);
 231                        total += lu;
 232                        sub += lu;
 233                }
 234        }
 235end:
 236        gettimeofday(&t1, NULL);
 237        delta_usec = (t1.tv_sec - t0.tv_sec) * 1000000 + t1.tv_usec - t0.tv_usec;
 238
 239        throughput = 0;
 240        if (delta_usec)
 241                throughput = total * 8.0 / (double)delta_usec / 1000.0;
 242        getrusage(RUSAGE_THREAD, &ru);
 243        if (total > 1024*1024) {
 244                unsigned long total_usec;
 245                unsigned long mb = total >> 20;
 246                total_usec = 1000000*ru.ru_utime.tv_sec + ru.ru_utime.tv_usec +
 247                             1000000*ru.ru_stime.tv_sec + ru.ru_stime.tv_usec;
 248                printf("received %lg MB (%lg %% mmap'ed) in %lg s, %lg Gbit\n"
 249                       "  cpu usage user:%lg sys:%lg, %lg usec per MB, %lu c-switches\n",
 250                                total / (1024.0 * 1024.0),
 251                                100.0*total_mmap/total,
 252                                (double)delta_usec / 1000000.0,
 253                                throughput,
 254                                (double)ru.ru_utime.tv_sec + (double)ru.ru_utime.tv_usec / 1000000.0,
 255                                (double)ru.ru_stime.tv_sec + (double)ru.ru_stime.tv_usec / 1000000.0,
 256                                (double)total_usec/mb,
 257                                ru.ru_nvcsw);
 258        }
 259error:
 260        munmap(buffer, buffer_sz);
 261        close(fd);
 262        if (zflg)
 263                munmap(raddr, chunk_size + map_align);
 264        pthread_exit(0);
 265}
 266
 267static void apply_rcvsnd_buf(int fd)
 268{
 269        if (rcvbuf && setsockopt(fd, SOL_SOCKET,
 270                                 SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) == -1) {
 271                perror("setsockopt SO_RCVBUF");
 272        }
 273
 274        if (sndbuf && setsockopt(fd, SOL_SOCKET,
 275                                 SO_SNDBUF, &sndbuf, sizeof(sndbuf)) == -1) {
 276                perror("setsockopt SO_SNDBUF");
 277        }
 278}
 279
 280
 281static void setup_sockaddr(int domain, const char *str_addr,
 282                           struct sockaddr_storage *sockaddr)
 283{
 284        struct sockaddr_in6 *addr6 = (void *) sockaddr;
 285        struct sockaddr_in *addr4 = (void *) sockaddr;
 286
 287        switch (domain) {
 288        case PF_INET:
 289                memset(addr4, 0, sizeof(*addr4));
 290                addr4->sin_family = AF_INET;
 291                addr4->sin_port = htons(cfg_port);
 292                if (str_addr &&
 293                    inet_pton(AF_INET, str_addr, &(addr4->sin_addr)) != 1)
 294                        error(1, 0, "ipv4 parse error: %s", str_addr);
 295                break;
 296        case PF_INET6:
 297                memset(addr6, 0, sizeof(*addr6));
 298                addr6->sin6_family = AF_INET6;
 299                addr6->sin6_port = htons(cfg_port);
 300                if (str_addr &&
 301                    inet_pton(AF_INET6, str_addr, &(addr6->sin6_addr)) != 1)
 302                        error(1, 0, "ipv6 parse error: %s", str_addr);
 303                break;
 304        default:
 305                error(1, 0, "illegal domain");
 306        }
 307}
 308
 309static void do_accept(int fdlisten)
 310{
 311        pthread_attr_t attr;
 312        int rcvlowat;
 313
 314        pthread_attr_init(&attr);
 315        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 316
 317        rcvlowat = chunk_size;
 318        if (setsockopt(fdlisten, SOL_SOCKET, SO_RCVLOWAT,
 319                       &rcvlowat, sizeof(rcvlowat)) == -1) {
 320                perror("setsockopt SO_RCVLOWAT");
 321        }
 322
 323        apply_rcvsnd_buf(fdlisten);
 324
 325        while (1) {
 326                struct sockaddr_in addr;
 327                socklen_t addrlen = sizeof(addr);
 328                pthread_t th;
 329                int fd, res;
 330
 331                fd = accept(fdlisten, (struct sockaddr *)&addr, &addrlen);
 332                if (fd == -1) {
 333                        perror("accept");
 334                        continue;
 335                }
 336                res = pthread_create(&th, &attr, child_thread,
 337                                     (void *)(unsigned long)fd);
 338                if (res) {
 339                        errno = res;
 340                        perror("pthread_create");
 341                        close(fd);
 342                }
 343        }
 344}
 345
 346/* Each thread should reserve a big enough vma to avoid
 347 * spinlock collisions in ptl locks.
 348 * This size is 2MB on x86_64, and is exported in /proc/meminfo.
 349 */
 350static unsigned long default_huge_page_size(void)
 351{
 352        FILE *f = fopen("/proc/meminfo", "r");
 353        unsigned long hps = 0;
 354        size_t linelen = 0;
 355        char *line = NULL;
 356
 357        if (!f)
 358                return 0;
 359        while (getline(&line, &linelen, f) > 0) {
 360                if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
 361                        hps <<= 10;
 362                        break;
 363                }
 364        }
 365        free(line);
 366        fclose(f);
 367        return hps;
 368}
 369
 370int main(int argc, char *argv[])
 371{
 372        struct sockaddr_storage listenaddr, addr;
 373        unsigned int max_pacing_rate = 0;
 374        uint64_t total = 0;
 375        char *host = NULL;
 376        int fd, c, on = 1;
 377        size_t buffer_sz;
 378        char *buffer;
 379        int sflg = 0;
 380        int mss = 0;
 381
 382        while ((c = getopt(argc, argv, "46p:svr:w:H:zxkP:M:C:a:")) != -1) {
 383                switch (c) {
 384                case '4':
 385                        cfg_family = PF_INET;
 386                        cfg_alen = sizeof(struct sockaddr_in);
 387                        break;
 388                case '6':
 389                        cfg_family = PF_INET6;
 390                        cfg_alen = sizeof(struct sockaddr_in6);
 391                        break;
 392                case 'p':
 393                        cfg_port = atoi(optarg);
 394                        break;
 395                case 'H':
 396                        host = optarg;
 397                        break;
 398                case 's': /* server : listen for incoming connections */
 399                        sflg++;
 400                        break;
 401                case 'r':
 402                        rcvbuf = atoi(optarg);
 403                        break;
 404                case 'w':
 405                        sndbuf = atoi(optarg);
 406                        break;
 407                case 'z':
 408                        zflg = 1;
 409                        break;
 410                case 'M':
 411                        mss = atoi(optarg);
 412                        break;
 413                case 'x':
 414                        xflg = 1;
 415                        break;
 416                case 'k':
 417                        keepflag = 1;
 418                        break;
 419                case 'P':
 420                        max_pacing_rate = atoi(optarg) ;
 421                        break;
 422                case 'C':
 423                        chunk_size = atol(optarg);
 424                        break;
 425                case 'a':
 426                        map_align = atol(optarg);
 427                        break;
 428                default:
 429                        exit(1);
 430                }
 431        }
 432        if (!map_align) {
 433                map_align = default_huge_page_size();
 434                /* if really /proc/meminfo is not helping,
 435                 * we use the default x86_64 hugepagesize.
 436                 */
 437                if (!map_align)
 438                        map_align = 2*1024*1024;
 439        }
 440        if (sflg) {
 441                int fdlisten = socket(cfg_family, SOCK_STREAM, 0);
 442
 443                if (fdlisten == -1) {
 444                        perror("socket");
 445                        exit(1);
 446                }
 447                apply_rcvsnd_buf(fdlisten);
 448                setsockopt(fdlisten, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
 449
 450                setup_sockaddr(cfg_family, host, &listenaddr);
 451
 452                if (mss &&
 453                    setsockopt(fdlisten, IPPROTO_TCP, TCP_MAXSEG,
 454                               &mss, sizeof(mss)) == -1) {
 455                        perror("setsockopt TCP_MAXSEG");
 456                        exit(1);
 457                }
 458                if (bind(fdlisten, (const struct sockaddr *)&listenaddr, cfg_alen) == -1) {
 459                        perror("bind");
 460                        exit(1);
 461                }
 462                if (listen(fdlisten, 128) == -1) {
 463                        perror("listen");
 464                        exit(1);
 465                }
 466                do_accept(fdlisten);
 467        }
 468
 469        buffer = mmap_large_buffer(chunk_size, &buffer_sz);
 470        if (buffer == (char *)-1) {
 471                perror("mmap");
 472                exit(1);
 473        }
 474
 475        fd = socket(cfg_family, SOCK_STREAM, 0);
 476        if (fd == -1) {
 477                perror("socket");
 478                exit(1);
 479        }
 480        apply_rcvsnd_buf(fd);
 481
 482        setup_sockaddr(cfg_family, host, &addr);
 483
 484        if (mss &&
 485            setsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) {
 486                perror("setsockopt TCP_MAXSEG");
 487                exit(1);
 488        }
 489        if (connect(fd, (const struct sockaddr *)&addr, cfg_alen) == -1) {
 490                perror("connect");
 491                exit(1);
 492        }
 493        if (max_pacing_rate &&
 494            setsockopt(fd, SOL_SOCKET, SO_MAX_PACING_RATE,
 495                       &max_pacing_rate, sizeof(max_pacing_rate)) == -1)
 496                perror("setsockopt SO_MAX_PACING_RATE");
 497
 498        if (zflg && setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY,
 499                               &on, sizeof(on)) == -1) {
 500                perror("setsockopt SO_ZEROCOPY, (-z option disabled)");
 501                zflg = 0;
 502        }
 503        while (total < FILE_SZ) {
 504                int64_t wr = FILE_SZ - total;
 505
 506                if (wr > chunk_size)
 507                        wr = chunk_size;
 508                /* Note : we just want to fill the pipe with 0 bytes */
 509                wr = send(fd, buffer, (size_t)wr, zflg ? MSG_ZEROCOPY : 0);
 510                if (wr <= 0)
 511                        break;
 512                total += wr;
 513        }
 514        close(fd);
 515        munmap(buffer, buffer_sz);
 516        return 0;
 517}
 518