tools/testing/selftests/net/tcp_mmap.c

   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)
  75 static int cfg_family = AF_INET6;
  76 static socklen_t cfg_alen = sizeof(struct sockaddr_in6);
  77 static int cfg_port = 8787;
  78
  79 static int rcvbuf; /* Default: autotuning.  Can be set with -r <integer> option */
  80 static int sndbuf; /* Default: autotuning.  Can be set with -w <integer> option */
  81 static int zflg; /* zero copy option. (MSG_ZEROCOPY for sender, mmap() for receiver */
  82 static int xflg; /* hash received data (simple xor) (-h option) */
  83 static int keepflag; /* -k option: receiver shall keep all received file in memory (no munmap() calls) */
  84
  85 static size_t chunk_size  = 512*1024;
  86
  87 static size_t map_align;
  88
  89 unsigned long htotal;
  90
  91 static 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
  98 void 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 void *child_thread(void *arg)
 127 {
 128         unsigned long total_mmap = 0, total = 0;
 129         struct tcp_zerocopy_receive zc;
 130         unsigned long delta_usec;
 131         int flags = MAP_SHARED;
 132         struct timeval t0, t1;
 133         char *buffer = NULL;
 134         void *raddr = NULL;
 135         void *addr = NULL;
 136         double throughput;
 137         struct rusage ru;
 138         int lu, fd;
 139
 140         fd = (int)(unsigned long)arg;
 141
 142         gettimeofday(&t0, NULL);
 143
 144         fcntl(fd, F_SETFL, O_NDELAY);
 145         buffer = malloc(chunk_size);
 146         if (!buffer) {
 147                 perror("malloc");
 148                 goto error;
 149         }
 150         if (zflg) {
 151                 raddr = mmap(NULL, chunk_size + map_align, PROT_READ, flags, fd, 0);
 152                 if (raddr == (void *)-1) {
 153                         perror("mmap");
 154                         zflg = 0;
 155                 } else {
 156                         addr = ALIGN_PTR_UP(raddr, map_align);
 157                 }
 158         }
 159         while (1) {
 160                 struct pollfd pfd = { .fd = fd, .events = POLLIN, };
 161                 int sub;
 162
 163                 poll(&pfd, 1, 10000);
 164                 if (zflg) {
 165                         socklen_t zc_len = sizeof(zc);
 166                         int res;
 167
 168                         memset(&zc, 0, sizeof(zc));
 169                         zc.address = (__u64)((unsigned long)addr);
 170                         zc.length = chunk_size;
 171
 172                         res = getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE,
 173                                          &zc, &zc_len);
 174                         if (res == -1)
 175                                 break;
 176
 177                         if (zc.length) {
 178                                 assert(zc.length <= chunk_size);
 179                                 total_mmap += zc.length;
 180                                 if (xflg)
 181                                         hash_zone(addr, zc.length);
 182                                 total += zc.length;
 183                         }
 184                         if (zc.recv_skip_hint) {
 185                                 assert(zc.recv_skip_hint <= chunk_size);
 186                                 lu = read(fd, buffer, zc.recv_skip_hint);
 187                                 if (lu > 0) {
 188                                         if (xflg)
 189                                                 hash_zone(buffer, lu);
 190                                         total += lu;
 191                                 }
 192                         }
 193                         continue;
 194                 }
 195                 sub = 0;
 196                 while (sub < chunk_size) {
 197                         lu = read(fd, buffer + sub, chunk_size - sub);
 198                         if (lu == 0)
 199                                 goto end;
 200                         if (lu < 0)
 201                                 break;
 202                         if (xflg)
 203                                 hash_zone(buffer + sub, lu);
 204                         total += lu;
 205                         sub += lu;
 206                 }
 207         }
 208 end:
 209         gettimeofday(&t1, NULL);
 210         delta_usec = (t1.tv_sec - t0.tv_sec) * 1000000 + t1.tv_usec - t0.tv_usec;
 211
 212         throughput = 0;
 213         if (delta_usec)
 214                 throughput = total * 8.0 / (double)delta_usec / 1000.0;
 215         getrusage(RUSAGE_THREAD, &ru);
 216         if (total > 1024*1024) {
 217                 unsigned long total_usec;
 218                 unsigned long mb = total >> 20;
 219                 total_usec = 1000000*ru.ru_utime.tv_sec + ru.ru_utime.tv_usec +
 220                              1000000*ru.ru_stime.tv_sec + ru.ru_stime.tv_usec;
 221                 printf("received %lg MB (%lg %% mmap'ed) in %lg s, %lg Gbit\n"
 222                        "  cpu usage user:%lg sys:%lg, %lg usec per MB, %lu c-switches\n",
 223                                 total / (1024.0 * 1024.0),
 224                                 100.0*total_mmap/total,
 225                                 (double)delta_usec / 1000000.0,
 226                                 throughput,
 227                                 (double)ru.ru_utime.tv_sec + (double)ru.ru_utime.tv_usec / 1000000.0,
 228                                 (double)ru.ru_stime.tv_sec + (double)ru.ru_stime.tv_usec / 1000000.0,
 229                                 (double)total_usec/mb,
 230                                 ru.ru_nvcsw);
 231         }
 232 error:
 233         free(buffer);
 234         close(fd);
 235         if (zflg)
 236                 munmap(raddr, chunk_size + map_align);
 237         pthread_exit(0);
 238 }
 239
 240 static void apply_rcvsnd_buf(int fd)
 241 {
 242         if (rcvbuf && setsockopt(fd, SOL_SOCKET,
 243                                  SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) == -1) {
 244                 perror("setsockopt SO_RCVBUF");
 245         }
 246
 247         if (sndbuf && setsockopt(fd, SOL_SOCKET,
 248                                  SO_SNDBUF, &sndbuf, sizeof(sndbuf)) == -1) {
 249                 perror("setsockopt SO_SNDBUF");
 250         }
 251 }
 252
 253
 254 static void setup_sockaddr(int domain, const char *str_addr,
 255                            struct sockaddr_storage *sockaddr)
 256 {
 257         struct sockaddr_in6 *addr6 = (void *) sockaddr;
 258         struct sockaddr_in *addr4 = (void *) sockaddr;
 259
 260         switch (domain) {
 261         case PF_INET:
 262                 memset(addr4, 0, sizeof(*addr4));
 263                 addr4->sin_family = AF_INET;
 264                 addr4->sin_port = htons(cfg_port);
 265                 if (str_addr &&
 266                     inet_pton(AF_INET, str_addr, &(addr4->sin_addr)) != 1)
 267                         error(1, 0, "ipv4 parse error: %s", str_addr);
 268                 break;
 269         case PF_INET6:
 270                 memset(addr6, 0, sizeof(*addr6));
 271                 addr6->sin6_family = AF_INET6;
 272                 addr6->sin6_port = htons(cfg_port);
 273                 if (str_addr &&
 274                     inet_pton(AF_INET6, str_addr, &(addr6->sin6_addr)) != 1)
 275                         error(1, 0, "ipv6 parse error: %s", str_addr);
 276                 break;
 277         default:
 278                 error(1, 0, "illegal domain");
 279         }
 280 }
 281
 282 static void do_accept(int fdlisten)
 283 {
 284         pthread_attr_t attr;
 285         int rcvlowat;
 286
 287         pthread_attr_init(&attr);
 288         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 289
 290         rcvlowat = chunk_size;
 291         if (setsockopt(fdlisten, SOL_SOCKET, SO_RCVLOWAT,
 292                        &rcvlowat, sizeof(rcvlowat)) == -1) {
 293                 perror("setsockopt SO_RCVLOWAT");
 294         }
 295
 296         apply_rcvsnd_buf(fdlisten);
 297
 298         while (1) {
 299                 struct sockaddr_in addr;
 300                 socklen_t addrlen = sizeof(addr);
 301                 pthread_t th;
 302                 int fd, res;
 303
 304                 fd = accept(fdlisten, (struct sockaddr *)&addr, &addrlen);
 305                 if (fd == -1) {
 306                         perror("accept");
 307                         continue;
 308                 }
 309                 res = pthread_create(&th, &attr, child_thread,
 310                                      (void *)(unsigned long)fd);
 311                 if (res) {
 312                         errno = res;
 313                         perror("pthread_create");
 314                         close(fd);
 315                 }
 316         }
 317 }
 318
 319 /* Each thread should reserve a big enough vma to avoid
 320  * spinlock collisions in ptl locks.
 321  * This size is 2MB on x86_64, and is exported in /proc/meminfo.
 322  */
 323 static unsigned long default_huge_page_size(void)
 324 {
 325         FILE *f = fopen("/proc/meminfo", "r");
 326         unsigned long hps = 0;
 327         size_t linelen = 0;
 328         char *line = NULL;
 329
 330         if (!f)
 331                 return 0;
 332         while (getline(&line, &linelen, f) > 0) {
 333                 if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
 334                         hps <<= 10;
 335                         break;
 336                 }
 337         }
 338         free(line);
 339         fclose(f);
 340         return hps;
 341 }
 342
 343 int main(int argc, char *argv[])
 344 {
 345         struct sockaddr_storage listenaddr, addr;
 346         unsigned int max_pacing_rate = 0;
 347         size_t total = 0;
 348         char *host = NULL;
 349         int fd, c, on = 1;
 350         char *buffer;
 351         int sflg = 0;
 352         int mss = 0;
 353
 354         while ((c = getopt(argc, argv, "46p:svr:w:H:zxkP:M:C:a:")) != -1) {
 355                 switch (c) {
 356                 case '4':
 357                         cfg_family = PF_INET;
 358                         cfg_alen = sizeof(struct sockaddr_in);
 359                         break;
 360                 case '6':
 361                         cfg_family = PF_INET6;
 362                         cfg_alen = sizeof(struct sockaddr_in6);
 363                         break;
 364                 case 'p':
 365                         cfg_port = atoi(optarg);
 366                         break;
 367                 case 'H':
 368                         host = optarg;
 369                         break;
 370                 case 's': /* server : listen for incoming connections */
 371                         sflg++;
 372                         break;
 373                 case 'r':
 374                         rcvbuf = atoi(optarg);
 375                         break;
 376                 case 'w':
 377                         sndbuf = atoi(optarg);
 378                         break;
 379                 case 'z':
 380                         zflg = 1;
 381                         break;
 382                 case 'M':
 383                         mss = atoi(optarg);
 384                         break;
 385                 case 'x':
 386                         xflg = 1;
 387                         break;
 388                 case 'k':
 389                         keepflag = 1;
 390                         break;
 391                 case 'P':
 392                         max_pacing_rate = atoi(optarg) ;
 393                         break;
 394                 case 'C':
 395                         chunk_size = atol(optarg);
 396                         break;
 397                 case 'a':
 398                         map_align = atol(optarg);
 399                         break;
 400                 default:
 401                         exit(1);
 402                 }
 403         }
 404         if (!map_align) {
 405                 map_align = default_huge_page_size();
 406                 /* if really /proc/meminfo is not helping,
 407                  * we use the default x86_64 hugepagesize.
 408                  */
 409                 if (!map_align)
 410                         map_align = 2*1024*1024;
 411         }
 412         if (sflg) {
 413                 int fdlisten = socket(cfg_family, SOCK_STREAM, 0);
 414
 415                 if (fdlisten == -1) {
 416                         perror("socket");
 417                         exit(1);
 418                 }
 419                 apply_rcvsnd_buf(fdlisten);
 420                 setsockopt(fdlisten, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
 421
 422                 setup_sockaddr(cfg_family, host, &listenaddr);
 423
 424                 if (mss &&
 425                     setsockopt(fdlisten, IPPROTO_TCP, TCP_MAXSEG,
 426                                &mss, sizeof(mss)) == -1) {
 427                         perror("setsockopt TCP_MAXSEG");
 428                         exit(1);
 429                 }
 430                 if (bind(fdlisten, (const struct sockaddr *)&listenaddr, cfg_alen) == -1) {
 431                         perror("bind");
 432                         exit(1);
 433                 }
 434                 if (listen(fdlisten, 128) == -1) {
 435                         perror("listen");
 436                         exit(1);
 437                 }
 438                 do_accept(fdlisten);
 439         }
 440         buffer = mmap(NULL, chunk_size, PROT_READ | PROT_WRITE,
 441                               MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 442         if (buffer == (char *)-1) {
 443                 perror("mmap");
 444                 exit(1);
 445         }
 446
 447         fd = socket(cfg_family, SOCK_STREAM, 0);
 448         if (fd == -1) {
 449                 perror("socket");
 450                 exit(1);
 451         }
 452         apply_rcvsnd_buf(fd);
 453
 454         setup_sockaddr(cfg_family, host, &addr);
 455
 456         if (mss &&
 457             setsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) {
 458                 perror("setsockopt TCP_MAXSEG");
 459                 exit(1);
 460         }
 461         if (connect(fd, (const struct sockaddr *)&addr, cfg_alen) == -1) {
 462                 perror("connect");
 463                 exit(1);
 464         }
 465         if (max_pacing_rate &&
 466             setsockopt(fd, SOL_SOCKET, SO_MAX_PACING_RATE,
 467                        &max_pacing_rate, sizeof(max_pacing_rate)) == -1)
 468                 perror("setsockopt SO_MAX_PACING_RATE");
 469
 470         if (zflg && setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY,
 471                                &on, sizeof(on)) == -1) {
 472                 perror("setsockopt SO_ZEROCOPY, (-z option disabled)");
 473                 zflg = 0;
 474         }
 475         while (total < FILE_SZ) {
 476                 ssize_t wr = FILE_SZ - total;
 477
 478                 if (wr > chunk_size)
 479                         wr = chunk_size;
 480                 /* Note : we just want to fill the pipe with 0 bytes */
 481                 wr = send(fd, buffer, wr, zflg ? MSG_ZEROCOPY : 0);
 482                 if (wr <= 0)
 483                         break;
 484                 total += wr;
 485         }
 486         close(fd);
 487         munmap(buffer, chunk_size);
 488         return 0;
 489 }