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
55 bool outFlag = true;
56 int minRate = 1000; /* cgroup rate limit in Mbps */
57 int rate = 1000; /* can grow if rate conserving is enabled */
58 int dur = 1;
59 bool stats_flag;
60 bool loopback_flag;
61 bool debugFlag;
62 bool work_conserving_flag;
63 bool no_cn_flag;
64 bool edt_flag;
65
66 static void Usage(void);
67 static void read_trace_pipe2(void);
68 static void do_error(char *msg, bool errno_flag);
69
70 #define DEBUGFS "/sys/kernel/debug/tracing/"
71
72 static struct bpf_program *bpf_prog;
73 static struct bpf_object *obj;
74 static int queue_stats_fd;
75
read_trace_pipe2(void)76 static 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
do_error(char * msg,bool errno_flag)112 static 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
prog_load(char * prog)121 static 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
149 err:
150 bpf_object__close(obj);
151 return 1;
152 }
153
run_bpf_prog(char * prog,int cg_id)154 static 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 fclose(fout);
312 } else if (stats_flag && qstats.lastPacketTime >
313 qstats.firstPacketTime) {
314 long long delta_us = (qstats.lastPacketTime -
315 qstats.firstPacketTime)/1000;
316 unsigned int rate_mbps = ((qstats.bytes_total -
317 qstats.bytes_dropped) * 8 /
318 delta_us);
319 double percent_pkts, percent_bytes;
320 char fname[100];
321 FILE *fout;
322 int k;
323 static const char *returnValNames[] = {
324 "DROP_PKT",
325 "ALLOW_PKT",
326 "DROP_PKT_CWR",
327 "ALLOW_PKT_CWR"
328 };
329 #define RET_VAL_COUNT 4
330
331 // Future support of ingress
332 // if (!outFlag)
333 // sprintf(fname, "hbm.%d.in", cg_id);
334 // else
335 sprintf(fname, "hbm.%d.out", cg_id);
336 fout = fopen(fname, "w");
337 fprintf(fout, "id:%d\n", cg_id);
338 fprintf(fout, "rate_mbps:%d\n", rate_mbps);
339 fprintf(fout, "duration:%.1f secs\n",
340 (qstats.lastPacketTime - qstats.firstPacketTime) /
341 1000000000.0);
342 fprintf(fout, "packets:%d\n", (int)qstats.pkts_total);
343 fprintf(fout, "bytes_MB:%d\n", (int)(qstats.bytes_total /
344 1000000));
345 fprintf(fout, "pkts_dropped:%d\n", (int)qstats.pkts_dropped);
346 fprintf(fout, "bytes_dropped_MB:%d\n",
347 (int)(qstats.bytes_dropped /
348 1000000));
349 // Marked Pkts and Bytes
350 percent_pkts = (qstats.pkts_marked * 100.0) /
351 (qstats.pkts_total + 1);
352 percent_bytes = (qstats.bytes_marked * 100.0) /
353 (qstats.bytes_total + 1);
354 fprintf(fout, "pkts_marked_percent:%6.2f\n", percent_pkts);
355 fprintf(fout, "bytes_marked_percent:%6.2f\n", percent_bytes);
356
357 // Dropped Pkts and Bytes
358 percent_pkts = (qstats.pkts_dropped * 100.0) /
359 (qstats.pkts_total + 1);
360 percent_bytes = (qstats.bytes_dropped * 100.0) /
361 (qstats.bytes_total + 1);
362 fprintf(fout, "pkts_dropped_percent:%6.2f\n", percent_pkts);
363 fprintf(fout, "bytes_dropped_percent:%6.2f\n", percent_bytes);
364
365 // ECN CE markings
366 percent_pkts = (qstats.pkts_ecn_ce * 100.0) /
367 (qstats.pkts_total + 1);
368 fprintf(fout, "pkts_ecn_ce:%6.2f (%d)\n", percent_pkts,
369 (int)qstats.pkts_ecn_ce);
370
371 // Average cwnd
372 fprintf(fout, "avg cwnd:%d\n",
373 (int)(qstats.sum_cwnd / (qstats.sum_cwnd_cnt + 1)));
374 // Average rtt
375 fprintf(fout, "avg rtt:%d\n",
376 (int)(qstats.sum_rtt / (qstats.pkts_total + 1)));
377 // Average credit
378 if (edt_flag)
379 fprintf(fout, "avg credit_ms:%.03f\n",
380 (qstats.sum_credit /
381 (qstats.pkts_total + 1.0)) / 1000000.0);
382 else
383 fprintf(fout, "avg credit:%d\n",
384 (int)(qstats.sum_credit /
385 (1500 * ((int)qstats.pkts_total ) + 1)));
386
387 // Return values stats
388 for (k = 0; k < RET_VAL_COUNT; k++) {
389 percent_pkts = (qstats.returnValCount[k] * 100.0) /
390 (qstats.pkts_total + 1);
391 fprintf(fout, "%s:%6.2f (%d)\n", returnValNames[k],
392 percent_pkts, (int)qstats.returnValCount[k]);
393 }
394 fclose(fout);
395 }
396
397 if (debugFlag)
398 read_trace_pipe2();
399 goto cleanup;
400
401 err:
402 rc = 1;
403
404 cleanup:
405 bpf_link__destroy(link);
406 bpf_object__close(obj);
407
408 if (cg1 != -1)
409 close(cg1);
410
411 if (rc != 0)
412 cleanup_cgroup_environment();
413 return rc;
414 }
415
Usage(void)416 static void Usage(void)
417 {
418 printf("This program loads a cgroup skb BPF program to enforce\n"
419 "cgroup output (egress) bandwidth limits.\n\n"
420 "USAGE: hbm [-o] [-d] [-l] [-n <id>] [--no_cn] [-r <rate>]\n"
421 " [-s] [-t <secs>] [-w] [-h] [prog]\n"
422 " Where:\n"
423 " -o indicates egress direction (default)\n"
424 " -d print BPF trace debug buffer\n"
425 " --edt use fq's Earliest Departure Time\n"
426 " -l also limit flows using loopback\n"
427 " -n <#> to create cgroup \"/hbm#\" and attach prog\n"
428 " Default is /hbm1\n"
429 " --no_cn disable CN notifications\n"
430 " -r <rate> Rate in Mbps\n"
431 " -s Update HBM stats\n"
432 " -t <time> Exit after specified seconds (default is 0)\n"
433 " -w Work conserving flag. cgroup can increase\n"
434 " bandwidth beyond the rate limit specified\n"
435 " while there is available bandwidth. Current\n"
436 " implementation assumes there is only eth0\n"
437 " but can be extended to support multiple NICs\n"
438 " -h print this info\n"
439 " prog BPF program file name. Name defaults to\n"
440 " hbm_out_kern.o\n");
441 }
442
main(int argc,char ** argv)443 int main(int argc, char **argv)
444 {
445 char *prog = "hbm_out_kern.o";
446 int k;
447 int cg_id = 1;
448 char *optstring = "iodln:r:st:wh";
449 struct option loptions[] = {
450 {"no_cn", 0, NULL, 1},
451 {"edt", 0, NULL, 2},
452 {NULL, 0, NULL, 0}
453 };
454
455 while ((k = getopt_long(argc, argv, optstring, loptions, NULL)) != -1) {
456 switch (k) {
457 case 1:
458 no_cn_flag = true;
459 break;
460 case 2:
461 prog = "hbm_edt_kern.o";
462 edt_flag = true;
463 break;
464 case'o':
465 break;
466 case 'd':
467 debugFlag = true;
468 break;
469 case 'l':
470 loopback_flag = true;
471 break;
472 case 'n':
473 cg_id = atoi(optarg);
474 break;
475 case 'r':
476 minRate = atoi(optarg) * 1.024;
477 rate = minRate;
478 break;
479 case 's':
480 stats_flag = true;
481 break;
482 case 't':
483 dur = atoi(optarg);
484 break;
485 case 'w':
486 work_conserving_flag = true;
487 break;
488 case '?':
489 if (optopt == 'n' || optopt == 'r' || optopt == 't')
490 fprintf(stderr,
491 "Option -%c requires an argument.\n\n",
492 optopt);
493 case 'h':
494 __fallthrough;
495 default:
496 Usage();
497 return 0;
498 }
499 }
500
501 if (optind < argc)
502 prog = argv[optind];
503 printf("HBM prog: %s\n", prog != NULL ? prog : "NULL");
504
505 return run_bpf_prog(prog, cg_id);
506 }
507