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)) 125 126 127 static 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 | MAP_POPULATE, 141 -1, 0); 142 if (buffer != (void *)-1) 143 fprintf(stderr, "MAP_HUGETLB attempt failed, look at /sys/kernel/mm/hugepages for optimal performance\n"); 144 } 145 *allocated = sz; 146 return buffer; 147 } 148 149 void *child_thread(void *arg) 150 { 151 unsigned long total_mmap = 0, total = 0; 152 struct tcp_zerocopy_receive zc; 153 unsigned long delta_usec; 154 int flags = MAP_SHARED; 155 struct timeval t0, t1; 156 char *buffer = NULL; 157 void *raddr = NULL; 158 void *addr = NULL; 159 double throughput; 160 struct rusage ru; 161 size_t buffer_sz; 162 int lu, fd; 163 164 fd = (int)(unsigned long)arg; 165 166 gettimeofday(&t0, NULL); 167 168 fcntl(fd, F_SETFL, O_NDELAY); 169 buffer = mmap_large_buffer(chunk_size, &buffer_sz); 170 if (buffer == (void *)-1) { 171 perror("mmap"); 172 goto error; 173 } 174 if (zflg) { 175 raddr = mmap(NULL, chunk_size + map_align, PROT_READ, flags, fd, 0); 176 if (raddr == (void *)-1) { 177 perror("mmap"); 178 zflg = 0; 179 } else { 180 addr = ALIGN_PTR_UP(raddr, map_align); 181 } 182 } 183 while (1) { 184 struct pollfd pfd = { .fd = fd, .events = POLLIN, }; 185 int sub; 186 187 poll(&pfd, 1, 10000); 188 if (zflg) { 189 socklen_t zc_len = sizeof(zc); 190 int res; 191 192 memset(&zc, 0, sizeof(zc)); 193 zc.address = (__u64)((unsigned long)addr); 194 zc.length = chunk_size; 195 196 res = getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, 197 &zc, &zc_len); 198 if (res == -1) 199 break; 200 201 if (zc.length) { 202 assert(zc.length <= chunk_size); 203 total_mmap += zc.length; 204 if (xflg) 205 hash_zone(addr, zc.length); 206 /* It is more efficient to unmap the pages right now, 207 * instead of doing this in next TCP_ZEROCOPY_RECEIVE. 208 */ 209 madvise(addr, zc.length, MADV_DONTNEED); 210 total += zc.length; 211 } 212 if (zc.recv_skip_hint) { 213 assert(zc.recv_skip_hint <= chunk_size); 214 lu = read(fd, buffer, zc.recv_skip_hint); 215 if (lu > 0) { 216 if (xflg) 217 hash_zone(buffer, lu); 218 total += lu; 219 } 220 } 221 continue; 222 } 223 sub = 0; 224 while (sub < chunk_size) { 225 lu = read(fd, buffer + sub, chunk_size - sub); 226 if (lu == 0) 227 goto end; 228 if (lu < 0) 229 break; 230 if (xflg) 231 hash_zone(buffer + sub, lu); 232 total += lu; 233 sub += lu; 234 } 235 } 236 end: 237 gettimeofday(&t1, NULL); 238 delta_usec = (t1.tv_sec - t0.tv_sec) * 1000000 + t1.tv_usec - t0.tv_usec; 239 240 throughput = 0; 241 if (delta_usec) 242 throughput = total * 8.0 / (double)delta_usec / 1000.0; 243 getrusage(RUSAGE_THREAD, &ru); 244 if (total > 1024*1024) { 245 unsigned long total_usec; 246 unsigned long mb = total >> 20; 247 total_usec = 1000000*ru.ru_utime.tv_sec + ru.ru_utime.tv_usec + 248 1000000*ru.ru_stime.tv_sec + ru.ru_stime.tv_usec; 249 printf("received %lg MB (%lg %% mmap'ed) in %lg s, %lg Gbit\n" 250 " cpu usage user:%lg sys:%lg, %lg usec per MB, %lu c-switches\n", 251 total / (1024.0 * 1024.0), 252 100.0*total_mmap/total, 253 (double)delta_usec / 1000000.0, 254 throughput, 255 (double)ru.ru_utime.tv_sec + (double)ru.ru_utime.tv_usec / 1000000.0, 256 (double)ru.ru_stime.tv_sec + (double)ru.ru_stime.tv_usec / 1000000.0, 257 (double)total_usec/mb, 258 ru.ru_nvcsw); 259 } 260 error: 261 munmap(buffer, buffer_sz); 262 close(fd); 263 if (zflg) 264 munmap(raddr, chunk_size + map_align); 265 pthread_exit(0); 266 } 267 268 static void apply_rcvsnd_buf(int fd) 269 { 270 if (rcvbuf && setsockopt(fd, SOL_SOCKET, 271 SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) == -1) { 272 perror("setsockopt SO_RCVBUF"); 273 } 274 275 if (sndbuf && setsockopt(fd, SOL_SOCKET, 276 SO_SNDBUF, &sndbuf, sizeof(sndbuf)) == -1) { 277 perror("setsockopt SO_SNDBUF"); 278 } 279 } 280 281 282 static void setup_sockaddr(int domain, const char *str_addr, 283 struct sockaddr_storage *sockaddr) 284 { 285 struct sockaddr_in6 *addr6 = (void *) sockaddr; 286 struct sockaddr_in *addr4 = (void *) sockaddr; 287 288 switch (domain) { 289 case PF_INET: 290 memset(addr4, 0, sizeof(*addr4)); 291 addr4->sin_family = AF_INET; 292 addr4->sin_port = htons(cfg_port); 293 if (str_addr && 294 inet_pton(AF_INET, str_addr, &(addr4->sin_addr)) != 1) 295 error(1, 0, "ipv4 parse error: %s", str_addr); 296 break; 297 case PF_INET6: 298 memset(addr6, 0, sizeof(*addr6)); 299 addr6->sin6_family = AF_INET6; 300 addr6->sin6_port = htons(cfg_port); 301 if (str_addr && 302 inet_pton(AF_INET6, str_addr, &(addr6->sin6_addr)) != 1) 303 error(1, 0, "ipv6 parse error: %s", str_addr); 304 break; 305 default: 306 error(1, 0, "illegal domain"); 307 } 308 } 309 310 static void do_accept(int fdlisten) 311 { 312 pthread_attr_t attr; 313 int rcvlowat; 314 315 pthread_attr_init(&attr); 316 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 317 318 rcvlowat = chunk_size; 319 if (setsockopt(fdlisten, SOL_SOCKET, SO_RCVLOWAT, 320 &rcvlowat, sizeof(rcvlowat)) == -1) { 321 perror("setsockopt SO_RCVLOWAT"); 322 } 323 324 apply_rcvsnd_buf(fdlisten); 325 326 while (1) { 327 struct sockaddr_in addr; 328 socklen_t addrlen = sizeof(addr); 329 pthread_t th; 330 int fd, res; 331 332 fd = accept(fdlisten, (struct sockaddr *)&addr, &addrlen); 333 if (fd == -1) { 334 perror("accept"); 335 continue; 336 } 337 res = pthread_create(&th, &attr, child_thread, 338 (void *)(unsigned long)fd); 339 if (res) { 340 errno = res; 341 perror("pthread_create"); 342 close(fd); 343 } 344 } 345 } 346 347 /* Each thread should reserve a big enough vma to avoid 348 * spinlock collisions in ptl locks. 349 * This size is 2MB on x86_64, and is exported in /proc/meminfo. 350 */ 351 static unsigned long default_huge_page_size(void) 352 { 353 FILE *f = fopen("/proc/meminfo", "r"); 354 unsigned long hps = 0; 355 size_t linelen = 0; 356 char *line = NULL; 357 358 if (!f) 359 return 0; 360 while (getline(&line, &linelen, f) > 0) { 361 if (sscanf(line, "Hugepagesize: %lu kB", &hps) == 1) { 362 hps <<= 10; 363 break; 364 } 365 } 366 free(line); 367 fclose(f); 368 return hps; 369 } 370 371 int main(int argc, char *argv[]) 372 { 373 struct sockaddr_storage listenaddr, addr; 374 unsigned int max_pacing_rate = 0; 375 uint64_t total = 0; 376 char *host = NULL; 377 int fd, c, on = 1; 378 size_t buffer_sz; 379 char *buffer; 380 int sflg = 0; 381 int mss = 0; 382 383 while ((c = getopt(argc, argv, "46p:svr:w:H:zxkP:M:C:a:")) != -1) { 384 switch (c) { 385 case '4': 386 cfg_family = PF_INET; 387 cfg_alen = sizeof(struct sockaddr_in); 388 break; 389 case '6': 390 cfg_family = PF_INET6; 391 cfg_alen = sizeof(struct sockaddr_in6); 392 break; 393 case 'p': 394 cfg_port = atoi(optarg); 395 break; 396 case 'H': 397 host = optarg; 398 break; 399 case 's': /* server : listen for incoming connections */ 400 sflg++; 401 break; 402 case 'r': 403 rcvbuf = atoi(optarg); 404 break; 405 case 'w': 406 sndbuf = atoi(optarg); 407 break; 408 case 'z': 409 zflg = 1; 410 break; 411 case 'M': 412 mss = atoi(optarg); 413 break; 414 case 'x': 415 xflg = 1; 416 break; 417 case 'k': 418 keepflag = 1; 419 break; 420 case 'P': 421 max_pacing_rate = atoi(optarg) ; 422 break; 423 case 'C': 424 chunk_size = atol(optarg); 425 break; 426 case 'a': 427 map_align = atol(optarg); 428 break; 429 default: 430 exit(1); 431 } 432 } 433 if (!map_align) { 434 map_align = default_huge_page_size(); 435 /* if really /proc/meminfo is not helping, 436 * we use the default x86_64 hugepagesize. 437 */ 438 if (!map_align) 439 map_align = 2*1024*1024; 440 } 441 if (sflg) { 442 int fdlisten = socket(cfg_family, SOCK_STREAM, 0); 443 444 if (fdlisten == -1) { 445 perror("socket"); 446 exit(1); 447 } 448 apply_rcvsnd_buf(fdlisten); 449 setsockopt(fdlisten, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); 450 451 setup_sockaddr(cfg_family, host, &listenaddr); 452 453 if (mss && 454 setsockopt(fdlisten, IPPROTO_TCP, TCP_MAXSEG, 455 &mss, sizeof(mss)) == -1) { 456 perror("setsockopt TCP_MAXSEG"); 457 exit(1); 458 } 459 if (bind(fdlisten, (const struct sockaddr *)&listenaddr, cfg_alen) == -1) { 460 perror("bind"); 461 exit(1); 462 } 463 if (listen(fdlisten, 128) == -1) { 464 perror("listen"); 465 exit(1); 466 } 467 do_accept(fdlisten); 468 } 469 470 buffer = mmap_large_buffer(chunk_size, &buffer_sz); 471 if (buffer == (char *)-1) { 472 perror("mmap"); 473 exit(1); 474 } 475 476 fd = socket(cfg_family, SOCK_STREAM, 0); 477 if (fd == -1) { 478 perror("socket"); 479 exit(1); 480 } 481 apply_rcvsnd_buf(fd); 482 483 setup_sockaddr(cfg_family, host, &addr); 484 485 if (mss && 486 setsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) { 487 perror("setsockopt TCP_MAXSEG"); 488 exit(1); 489 } 490 if (connect(fd, (const struct sockaddr *)&addr, cfg_alen) == -1) { 491 perror("connect"); 492 exit(1); 493 } 494 if (max_pacing_rate && 495 setsockopt(fd, SOL_SOCKET, SO_MAX_PACING_RATE, 496 &max_pacing_rate, sizeof(max_pacing_rate)) == -1) 497 perror("setsockopt SO_MAX_PACING_RATE"); 498 499 if (zflg && setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY, 500 &on, sizeof(on)) == -1) { 501 perror("setsockopt SO_ZEROCOPY, (-z option disabled)"); 502 zflg = 0; 503 } 504 while (total < FILE_SZ) { 505 int64_t wr = FILE_SZ - total; 506 507 if (wr > chunk_size) 508 wr = chunk_size; 509 /* Note : we just want to fill the pipe with 0 bytes */ 510 wr = send(fd, buffer, (size_t)wr, zflg ? MSG_ZEROCOPY : 0); 511 if (wr <= 0) 512 break; 513 total += wr; 514 } 515 close(fd); 516 munmap(buffer, buffer_sz); 517 return 0; 518 } 519