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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 (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}