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1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2019 Facebook
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
7 *
8 * Example program for Host Bandwidth Managment
9 *
10 * This program loads a cgroup skb BPF program to enforce cgroup output
11 * (egress) or input (ingress) bandwidth limits.
12 *
13 * USAGE: hbm [-d] [-l] [-n <id>] [-r <rate>] [-s] [-t <secs>] [-w] [-h] [prog]
14 * Where:
15 * -d Print BPF trace debug buffer
16 * -l Also limit flows doing loopback
17 * -n <#> To create cgroup \"/hbm#\" and attach prog
18 * Default is /hbm1
19 * --no_cn Do not return cn notifications
20 * -r <rate> Rate limit in Mbps
21 * -s Get HBM stats (marked, dropped, etc.)
22 * -t <time> Exit after specified seconds (default is 0)
23 * -w Work conserving flag. cgroup can increase its bandwidth
24 * beyond the rate limit specified while there is available
25 * bandwidth. Current implementation assumes there is only
26 * NIC (eth0), but can be extended to support multiple NICs.
27 * Currrently only supported for egress.
28 * -h Print this info
29 * prog BPF program file name. Name defaults to hbm_out_kern.o
30 */
31
32#define _GNU_SOURCE
33
34#include <stdio.h>
35#include <stdlib.h>
36#include <assert.h>
37#include <sys/resource.h>
38#include <sys/time.h>
39#include <unistd.h>
40#include <errno.h>
41#include <fcntl.h>
42#include <linux/unistd.h>
43#include <linux/compiler.h>
44
45#include <linux/bpf.h>
46#include <bpf/bpf.h>
47#include <getopt.h>
48
49#include "bpf_rlimit.h"
50#include "cgroup_helpers.h"
51#include "hbm.h"
52#include "bpf_util.h"
53#include <bpf/libbpf.h>
54
55bool outFlag = true;
56int minRate = 1000; /* cgroup rate limit in Mbps */
57int rate = 1000; /* can grow if rate conserving is enabled */
58int dur = 1;
59bool stats_flag;
60bool loopback_flag;
61bool debugFlag;
62bool work_conserving_flag;
63bool no_cn_flag;
64bool edt_flag;
65
66static void Usage(void);
67static void read_trace_pipe2(void);
68static void do_error(char *msg, bool errno_flag);
69
70#define DEBUGFS "/sys/kernel/debug/tracing/"
71
72static struct bpf_program *bpf_prog;
73static struct bpf_object *obj;
74static int queue_stats_fd;
75
76static void read_trace_pipe2(void)
77{
78 int trace_fd;
79 FILE *outf;
80 char *outFname = "hbm_out.log";
81
82 trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
83 if (trace_fd < 0) {
84 printf("Error opening trace_pipe\n");
85 return;
86 }
87
88// Future support of ingress
89// if (!outFlag)
90// outFname = "hbm_in.log";
91 outf = fopen(outFname, "w");
92
93 if (outf == NULL)
94 printf("Error creating %s\n", outFname);
95
96 while (1) {
97 static char buf[4097];
98 ssize_t sz;
99
100 sz = read(trace_fd, buf, sizeof(buf) - 1);
101 if (sz > 0) {
102 buf[sz] = 0;
103 puts(buf);
104 if (outf != NULL) {
105 fprintf(outf, "%s\n", buf);
106 fflush(outf);
107 }
108 }
109 }
110}
111
112static void do_error(char *msg, bool errno_flag)
113{
114 if (errno_flag)
115 printf("ERROR: %s, errno: %d\n", msg, errno);
116 else
117 printf("ERROR: %s\n", msg);
118 exit(1);
119}
120
121static int prog_load(char *prog)
122{
123 obj = bpf_object__open_file(prog, NULL);
124 if (libbpf_get_error(obj)) {
125 printf("ERROR: opening BPF object file failed\n");
126 return 1;
127 }
128
129 /* load BPF program */
130 if (bpf_object__load(obj)) {
131 printf("ERROR: loading BPF object file failed\n");
132 goto err;
133 }
134
135 bpf_prog = bpf_object__find_program_by_title(obj, "cgroup_skb/egress");
136 if (!bpf_prog) {
137 printf("ERROR: finding a prog in obj file failed\n");
138 goto err;
139 }
140
141 queue_stats_fd = bpf_object__find_map_fd_by_name(obj, "queue_stats");
142 if (queue_stats_fd < 0) {
143 printf("ERROR: finding a map in obj file failed\n");
144 goto err;
145 }
146
147 return 0;
148
149err:
150 bpf_object__close(obj);
151 return 1;
152}
153
154static int run_bpf_prog(char *prog, int cg_id)
155{
156 struct hbm_queue_stats qstats = {0};
157 char cg_dir[100], cg_pin_path[100];
158 struct bpf_link *link = NULL;
159 int key = 0;
160 int cg1 = 0;
161 int rc = 0;
162
163 sprintf(cg_dir, "/hbm%d", cg_id);
164 rc = prog_load(prog);
165 if (rc != 0)
166 return rc;
167
168 if (setup_cgroup_environment()) {
169 printf("ERROR: setting cgroup environment\n");
170 goto err;
171 }
172 cg1 = create_and_get_cgroup(cg_dir);
173 if (!cg1) {
174 printf("ERROR: create_and_get_cgroup\n");
175 goto err;
176 }
177 if (join_cgroup(cg_dir)) {
178 printf("ERROR: join_cgroup\n");
179 goto err;
180 }
181
182 qstats.rate = rate;
183 qstats.stats = stats_flag ? 1 : 0;
184 qstats.loopback = loopback_flag ? 1 : 0;
185 qstats.no_cn = no_cn_flag ? 1 : 0;
186 if (bpf_map_update_elem(queue_stats_fd, &key, &qstats, BPF_ANY)) {
187 printf("ERROR: Could not update map element\n");
188 goto err;
189 }
190
191 if (!outFlag)
192 bpf_program__set_expected_attach_type(bpf_prog, BPF_CGROUP_INET_INGRESS);
193
194 link = bpf_program__attach_cgroup(bpf_prog, cg1);
195 if (libbpf_get_error(link)) {
196 fprintf(stderr, "ERROR: bpf_program__attach_cgroup failed\n");
197 goto err;
198 }
199
200 sprintf(cg_pin_path, "/sys/fs/bpf/hbm%d", cg_id);
201 rc = bpf_link__pin(link, cg_pin_path);
202 if (rc < 0) {
203 printf("ERROR: bpf_link__pin failed: %d\n", rc);
204 goto err;
205 }
206
207 if (work_conserving_flag) {
208 struct timeval t0, t_last, t_new;
209 FILE *fin;
210 unsigned long long last_eth_tx_bytes, new_eth_tx_bytes;
211 signed long long last_cg_tx_bytes, new_cg_tx_bytes;
212 signed long long delta_time, delta_bytes, delta_rate;
213 int delta_ms;
214#define DELTA_RATE_CHECK 10000 /* in us */
215#define RATE_THRESHOLD 9500000000 /* 9.5 Gbps */
216
217 bpf_map_lookup_elem(queue_stats_fd, &key, &qstats);
218 if (gettimeofday(&t0, NULL) < 0)
219 do_error("gettimeofday failed", true);
220 t_last = t0;
221 fin = fopen("/sys/class/net/eth0/statistics/tx_bytes", "r");
222 if (fscanf(fin, "%llu", &last_eth_tx_bytes) != 1)
223 do_error("fscanf fails", false);
224 fclose(fin);
225 last_cg_tx_bytes = qstats.bytes_total;
226 while (true) {
227 usleep(DELTA_RATE_CHECK);
228 if (gettimeofday(&t_new, NULL) < 0)
229 do_error("gettimeofday failed", true);
230 delta_ms = (t_new.tv_sec - t0.tv_sec) * 1000 +
231 (t_new.tv_usec - t0.tv_usec)/1000;
232 if (delta_ms > dur * 1000)
233 break;
234 delta_time = (t_new.tv_sec - t_last.tv_sec) * 1000000 +
235 (t_new.tv_usec - t_last.tv_usec);
236 if (delta_time == 0)
237 continue;
238 t_last = t_new;
239 fin = fopen("/sys/class/net/eth0/statistics/tx_bytes",
240 "r");
241 if (fscanf(fin, "%llu", &new_eth_tx_bytes) != 1)
242 do_error("fscanf fails", false);
243 fclose(fin);
244 printf(" new_eth_tx_bytes:%llu\n",
245 new_eth_tx_bytes);
246 bpf_map_lookup_elem(queue_stats_fd, &key, &qstats);
247 new_cg_tx_bytes = qstats.bytes_total;
248 delta_bytes = new_eth_tx_bytes - last_eth_tx_bytes;
249 last_eth_tx_bytes = new_eth_tx_bytes;
250 delta_rate = (delta_bytes * 8000000) / delta_time;
251 printf("%5d - eth_rate:%.1fGbps cg_rate:%.3fGbps",
252 delta_ms, delta_rate/1000000000.0,
253 rate/1000.0);
254 if (delta_rate < RATE_THRESHOLD) {
255 /* can increase cgroup rate limit, but first
256 * check if we are using the current limit.
257 * Currently increasing by 6.25%, unknown
258 * if that is the optimal rate.
259 */
260 int rate_diff100;
261
262 delta_bytes = new_cg_tx_bytes -
263 last_cg_tx_bytes;
264 last_cg_tx_bytes = new_cg_tx_bytes;
265 delta_rate = (delta_bytes * 8000000) /
266 delta_time;
267 printf(" rate:%.3fGbps",
268 delta_rate/1000000000.0);
269 rate_diff100 = (((long long)rate)*1000000 -
270 delta_rate) * 100 /
271 (((long long) rate) * 1000000);
272 printf(" rdiff:%d", rate_diff100);
273 if (rate_diff100 <= 3) {
274 rate += (rate >> 4);
275 if (rate > RATE_THRESHOLD / 1000000)
276 rate = RATE_THRESHOLD / 1000000;
277 qstats.rate = rate;
278 printf(" INC\n");
279 } else {
280 printf("\n");
281 }
282 } else {
283 /* Need to decrease cgroup rate limit.
284 * Currently decreasing by 12.5%, unknown
285 * if that is optimal
286 */
287 printf(" DEC\n");
288 rate -= (rate >> 3);
289 if (rate < minRate)
290 rate = minRate;
291 qstats.rate = rate;
292 }
293 if (bpf_map_update_elem(queue_stats_fd, &key, &qstats, BPF_ANY))
294 do_error("update map element fails", false);
295 }
296 } else {
297 sleep(dur);
298 }
299 // Get stats!
300 if (stats_flag && bpf_map_lookup_elem(queue_stats_fd, &key, &qstats)) {
301 char fname[100];
302 FILE *fout;
303
304 if (!outFlag)
305 sprintf(fname, "hbm.%d.in", cg_id);
306 else
307 sprintf(fname, "hbm.%d.out", cg_id);
308 fout = fopen(fname, "w");
309 fprintf(fout, "id:%d\n", cg_id);
310 fprintf(fout, "ERROR: Could not lookup queue_stats\n");
311 } else if (stats_flag && qstats.lastPacketTime >
312 qstats.firstPacketTime) {
313 long long delta_us = (qstats.lastPacketTime -
314 qstats.firstPacketTime)/1000;
315 unsigned int rate_mbps = ((qstats.bytes_total -
316 qstats.bytes_dropped) * 8 /
317 delta_us);
318 double percent_pkts, percent_bytes;
319 char fname[100];
320 FILE *fout;
321 int k;
322 static const char *returnValNames[] = {
323 "DROP_PKT",
324 "ALLOW_PKT",
325 "DROP_PKT_CWR",
326 "ALLOW_PKT_CWR"
327 };
328#define RET_VAL_COUNT 4
329
330// Future support of ingress
331// if (!outFlag)
332// sprintf(fname, "hbm.%d.in", cg_id);
333// else
334 sprintf(fname, "hbm.%d.out", cg_id);
335 fout = fopen(fname, "w");
336 fprintf(fout, "id:%d\n", cg_id);
337 fprintf(fout, "rate_mbps:%d\n", rate_mbps);
338 fprintf(fout, "duration:%.1f secs\n",
339 (qstats.lastPacketTime - qstats.firstPacketTime) /
340 1000000000.0);
341 fprintf(fout, "packets:%d\n", (int)qstats.pkts_total);
342 fprintf(fout, "bytes_MB:%d\n", (int)(qstats.bytes_total /
343 1000000));
344 fprintf(fout, "pkts_dropped:%d\n", (int)qstats.pkts_dropped);
345 fprintf(fout, "bytes_dropped_MB:%d\n",
346 (int)(qstats.bytes_dropped /
347 1000000));
348 // Marked Pkts and Bytes
349 percent_pkts = (qstats.pkts_marked * 100.0) /
350 (qstats.pkts_total + 1);
351 percent_bytes = (qstats.bytes_marked * 100.0) /
352 (qstats.bytes_total + 1);
353 fprintf(fout, "pkts_marked_percent:%6.2f\n", percent_pkts);
354 fprintf(fout, "bytes_marked_percent:%6.2f\n", percent_bytes);
355
356 // Dropped Pkts and Bytes
357 percent_pkts = (qstats.pkts_dropped * 100.0) /
358 (qstats.pkts_total + 1);
359 percent_bytes = (qstats.bytes_dropped * 100.0) /
360 (qstats.bytes_total + 1);
361 fprintf(fout, "pkts_dropped_percent:%6.2f\n", percent_pkts);
362 fprintf(fout, "bytes_dropped_percent:%6.2f\n", percent_bytes);
363
364 // ECN CE markings
365 percent_pkts = (qstats.pkts_ecn_ce * 100.0) /
366 (qstats.pkts_total + 1);
367 fprintf(fout, "pkts_ecn_ce:%6.2f (%d)\n", percent_pkts,
368 (int)qstats.pkts_ecn_ce);
369
370 // Average cwnd
371 fprintf(fout, "avg cwnd:%d\n",
372 (int)(qstats.sum_cwnd / (qstats.sum_cwnd_cnt + 1)));
373 // Average rtt
374 fprintf(fout, "avg rtt:%d\n",
375 (int)(qstats.sum_rtt / (qstats.pkts_total + 1)));
376 // Average credit
377 if (edt_flag)
378 fprintf(fout, "avg credit_ms:%.03f\n",
379 (qstats.sum_credit /
380 (qstats.pkts_total + 1.0)) / 1000000.0);
381 else
382 fprintf(fout, "avg credit:%d\n",
383 (int)(qstats.sum_credit /
384 (1500 * ((int)qstats.pkts_total ) + 1)));
385
386 // Return values stats
387 for (k = 0; k < RET_VAL_COUNT; k++) {
388 percent_pkts = (qstats.returnValCount[k] * 100.0) /
389 (qstats.pkts_total + 1);
390 fprintf(fout, "%s:%6.2f (%d)\n", returnValNames[k],
391 percent_pkts, (int)qstats.returnValCount[k]);
392 }
393 fclose(fout);
394 }
395
396 if (debugFlag)
397 read_trace_pipe2();
398 goto cleanup;
399
400err:
401 rc = 1;
402
403cleanup:
404 bpf_link__destroy(link);
405 bpf_object__close(obj);
406
407 if (cg1 != -1)
408 close(cg1);
409
410 if (rc != 0)
411 cleanup_cgroup_environment();
412 return rc;
413}
414
415static void Usage(void)
416{
417 printf("This program loads a cgroup skb BPF program to enforce\n"
418 "cgroup output (egress) bandwidth limits.\n\n"
419 "USAGE: hbm [-o] [-d] [-l] [-n <id>] [--no_cn] [-r <rate>]\n"
420 " [-s] [-t <secs>] [-w] [-h] [prog]\n"
421 " Where:\n"
422 " -o indicates egress direction (default)\n"
423 " -d print BPF trace debug buffer\n"
424 " --edt use fq's Earliest Departure Time\n"
425 " -l also limit flows using loopback\n"
426 " -n <#> to create cgroup \"/hbm#\" and attach prog\n"
427 " Default is /hbm1\n"
428 " --no_cn disable CN notifications\n"
429 " -r <rate> Rate in Mbps\n"
430 " -s Update HBM stats\n"
431 " -t <time> Exit after specified seconds (default is 0)\n"
432 " -w Work conserving flag. cgroup can increase\n"
433 " bandwidth beyond the rate limit specified\n"
434 " while there is available bandwidth. Current\n"
435 " implementation assumes there is only eth0\n"
436 " but can be extended to support multiple NICs\n"
437 " -h print this info\n"
438 " prog BPF program file name. Name defaults to\n"
439 " hbm_out_kern.o\n");
440}
441
442int main(int argc, char **argv)
443{
444 char *prog = "hbm_out_kern.o";
445 int k;
446 int cg_id = 1;
447 char *optstring = "iodln:r:st:wh";
448 struct option loptions[] = {
449 {"no_cn", 0, NULL, 1},
450 {"edt", 0, NULL, 2},
451 {NULL, 0, NULL, 0}
452 };
453
454 while ((k = getopt_long(argc, argv, optstring, loptions, NULL)) != -1) {
455 switch (k) {
456 case 1:
457 no_cn_flag = true;
458 break;
459 case 2:
460 prog = "hbm_edt_kern.o";
461 edt_flag = true;
462 break;
463 case'o':
464 break;
465 case 'd':
466 debugFlag = true;
467 break;
468 case 'l':
469 loopback_flag = true;
470 break;
471 case 'n':
472 cg_id = atoi(optarg);
473 break;
474 case 'r':
475 minRate = atoi(optarg) * 1.024;
476 rate = minRate;
477 break;
478 case 's':
479 stats_flag = true;
480 break;
481 case 't':
482 dur = atoi(optarg);
483 break;
484 case 'w':
485 work_conserving_flag = true;
486 break;
487 case '?':
488 if (optopt == 'n' || optopt == 'r' || optopt == 't')
489 fprintf(stderr,
490 "Option -%c requires an argument.\n\n",
491 optopt);
492 case 'h':
493 __fallthrough;
494 default:
495 Usage();
496 return 0;
497 }
498 }
499
500 if (optind < argc)
501 prog = argv[optind];
502 printf("HBM prog: %s\n", prog != NULL ? prog : "NULL");
503
504 return run_bpf_prog(prog, cg_id);
505}