xref: /openbmc/linux/samples/bpf/hbm.c (revision aeb64ff3) 
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 
44 #include <linux/bpf.h>
45 #include <bpf/bpf.h>
46 #include <getopt.h>
47 
48 #include "bpf_load.h"
49 #include "bpf_rlimit.h"
50 #include "cgroup_helpers.h"
51 #include "hbm.h"
52 #include "bpf_util.h"
53 #include "bpf.h"
54 #include "libbpf.h"
55 
56 bool outFlag = true;
57 int minRate = 1000;		/* cgroup rate limit in Mbps */
58 int rate = 1000;		/* can grow if rate conserving is enabled */
59 int dur = 1;
60 bool stats_flag;
61 bool loopback_flag;
62 bool debugFlag;
63 bool work_conserving_flag;
64 bool no_cn_flag;
65 bool edt_flag;
66 
67 static void Usage(void);
68 static void read_trace_pipe2(void);
69 static void do_error(char *msg, bool errno_flag);
70 
71 #define DEBUGFS "/sys/kernel/debug/tracing/"
72 
73 struct bpf_object *obj;
74 int bpfprog_fd;
75 int cgroup_storage_fd;
76 
77 static void read_trace_pipe2(void)
78 {
79 	int trace_fd;
80 	FILE *outf;
81 	char *outFname = "hbm_out.log";
82 
83 	trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
84 	if (trace_fd < 0) {
85 		printf("Error opening trace_pipe\n");
86 		return;
87 	}
88 
89 //	Future support of ingress
90 //	if (!outFlag)
91 //		outFname = "hbm_in.log";
92 	outf = fopen(outFname, "w");
93 
94 	if (outf == NULL)
95 		printf("Error creating %s\n", outFname);
96 
97 	while (1) {
98 		static char buf[4097];
99 		ssize_t sz;
100 
101 		sz = read(trace_fd, buf, sizeof(buf) - 1);
102 		if (sz > 0) {
103 			buf[sz] = 0;
104 			puts(buf);
105 			if (outf != NULL) {
106 				fprintf(outf, "%s\n", buf);
107 				fflush(outf);
108 			}
109 		}
110 	}
111 }
112 
113 static void do_error(char *msg, bool errno_flag)
114 {
115 	if (errno_flag)
116 		printf("ERROR: %s, errno: %d\n", msg, errno);
117 	else
118 		printf("ERROR: %s\n", msg);
119 	exit(1);
120 }
121 
122 static int prog_load(char *prog)
123 {
124 	struct bpf_prog_load_attr prog_load_attr = {
125 		.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
126 		.file = prog,
127 		.expected_attach_type = BPF_CGROUP_INET_EGRESS,
128 	};
129 	int map_fd;
130 	struct bpf_map *map;
131 
132 	int ret = 0;
133 
134 	if (access(prog, O_RDONLY) < 0) {
135 		printf("Error accessing file %s: %s\n", prog, strerror(errno));
136 		return 1;
137 	}
138 	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &bpfprog_fd))
139 		ret = 1;
140 	if (!ret) {
141 		map = bpf_object__find_map_by_name(obj, "queue_stats");
142 		map_fd = bpf_map__fd(map);
143 		if (map_fd < 0) {
144 			printf("Map not found: %s\n", strerror(map_fd));
145 			ret = 1;
146 		}
147 	}
148 
149 	if (ret) {
150 		printf("ERROR: bpf_prog_load_xattr failed for: %s\n", prog);
151 		printf("  Output from verifier:\n%s\n------\n", bpf_log_buf);
152 		ret = -1;
153 	} else {
154 		ret = map_fd;
155 	}
156 
157 	return ret;
158 }
159 
160 static int run_bpf_prog(char *prog, int cg_id)
161 {
162 	int map_fd;
163 	int rc = 0;
164 	int key = 0;
165 	int cg1 = 0;
166 	int type = BPF_CGROUP_INET_EGRESS;
167 	char cg_dir[100];
168 	struct hbm_queue_stats qstats = {0};
169 
170 	sprintf(cg_dir, "/hbm%d", cg_id);
171 	map_fd = prog_load(prog);
172 	if (map_fd  == -1)
173 		return 1;
174 
175 	if (setup_cgroup_environment()) {
176 		printf("ERROR: setting cgroup environment\n");
177 		goto err;
178 	}
179 	cg1 = create_and_get_cgroup(cg_dir);
180 	if (!cg1) {
181 		printf("ERROR: create_and_get_cgroup\n");
182 		goto err;
183 	}
184 	if (join_cgroup(cg_dir)) {
185 		printf("ERROR: join_cgroup\n");
186 		goto err;
187 	}
188 
189 	qstats.rate = rate;
190 	qstats.stats = stats_flag ? 1 : 0;
191 	qstats.loopback = loopback_flag ? 1 : 0;
192 	qstats.no_cn = no_cn_flag ? 1 : 0;
193 	if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY)) {
194 		printf("ERROR: Could not update map element\n");
195 		goto err;
196 	}
197 
198 	if (!outFlag)
199 		type = BPF_CGROUP_INET_INGRESS;
200 	if (bpf_prog_attach(bpfprog_fd, cg1, type, 0)) {
201 		printf("ERROR: bpf_prog_attach fails!\n");
202 		log_err("Attaching prog");
203 		goto err;
204 	}
205 
206 	if (work_conserving_flag) {
207 		struct timeval t0, t_last, t_new;
208 		FILE *fin;
209 		unsigned long long last_eth_tx_bytes, new_eth_tx_bytes;
210 		signed long long last_cg_tx_bytes, new_cg_tx_bytes;
211 		signed long long delta_time, delta_bytes, delta_rate;
212 		int delta_ms;
213 #define DELTA_RATE_CHECK 10000		/* in us */
214 #define RATE_THRESHOLD 9500000000	/* 9.5 Gbps */
215 
216 		bpf_map_lookup_elem(map_fd, &key, &qstats);
217 		if (gettimeofday(&t0, NULL) < 0)
218 			do_error("gettimeofday failed", true);
219 		t_last = t0;
220 		fin = fopen("/sys/class/net/eth0/statistics/tx_bytes", "r");
221 		if (fscanf(fin, "%llu", &last_eth_tx_bytes) != 1)
222 			do_error("fscanf fails", false);
223 		fclose(fin);
224 		last_cg_tx_bytes = qstats.bytes_total;
225 		while (true) {
226 			usleep(DELTA_RATE_CHECK);
227 			if (gettimeofday(&t_new, NULL) < 0)
228 				do_error("gettimeofday failed", true);
229 			delta_ms = (t_new.tv_sec - t0.tv_sec) * 1000 +
230 				(t_new.tv_usec - t0.tv_usec)/1000;
231 			if (delta_ms > dur * 1000)
232 				break;
233 			delta_time = (t_new.tv_sec - t_last.tv_sec) * 1000000 +
234 				(t_new.tv_usec - t_last.tv_usec);
235 			if (delta_time == 0)
236 				continue;
237 			t_last = t_new;
238 			fin = fopen("/sys/class/net/eth0/statistics/tx_bytes",
239 				    "r");
240 			if (fscanf(fin, "%llu", &new_eth_tx_bytes) != 1)
241 				do_error("fscanf fails", false);
242 			fclose(fin);
243 			printf("  new_eth_tx_bytes:%llu\n",
244 			       new_eth_tx_bytes);
245 			bpf_map_lookup_elem(map_fd, &key, &qstats);
246 			new_cg_tx_bytes = qstats.bytes_total;
247 			delta_bytes = new_eth_tx_bytes - last_eth_tx_bytes;
248 			last_eth_tx_bytes = new_eth_tx_bytes;
249 			delta_rate = (delta_bytes * 8000000) / delta_time;
250 			printf("%5d - eth_rate:%.1fGbps cg_rate:%.3fGbps",
251 			       delta_ms, delta_rate/1000000000.0,
252 			       rate/1000.0);
253 			if (delta_rate < RATE_THRESHOLD) {
254 				/* can increase cgroup rate limit, but first
255 				 * check if we are using the current limit.
256 				 * Currently increasing by 6.25%, unknown
257 				 * if that is the optimal rate.
258 				 */
259 				int rate_diff100;
260 
261 				delta_bytes = new_cg_tx_bytes -
262 					last_cg_tx_bytes;
263 				last_cg_tx_bytes = new_cg_tx_bytes;
264 				delta_rate = (delta_bytes * 8000000) /
265 					delta_time;
266 				printf(" rate:%.3fGbps",
267 				       delta_rate/1000000000.0);
268 				rate_diff100 = (((long long)rate)*1000000 -
269 						     delta_rate) * 100 /
270 					(((long long) rate) * 1000000);
271 				printf("  rdiff:%d", rate_diff100);
272 				if (rate_diff100  <= 3) {
273 					rate += (rate >> 4);
274 					if (rate > RATE_THRESHOLD / 1000000)
275 						rate = RATE_THRESHOLD / 1000000;
276 					qstats.rate = rate;
277 					printf(" INC\n");
278 				} else {
279 					printf("\n");
280 				}
281 			} else {
282 				/* Need to decrease cgroup rate limit.
283 				 * Currently decreasing by 12.5%, unknown
284 				 * if that is optimal
285 				 */
286 				printf(" DEC\n");
287 				rate -= (rate >> 3);
288 				if (rate < minRate)
289 					rate = minRate;
290 				qstats.rate = rate;
291 			}
292 			if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY))
293 				do_error("update map element fails", false);
294 		}
295 	} else {
296 		sleep(dur);
297 	}
298 	// Get stats!
299 	if (stats_flag && bpf_map_lookup_elem(map_fd, &key, &qstats)) {
300 		char fname[100];
301 		FILE *fout;
302 
303 		if (!outFlag)
304 			sprintf(fname, "hbm.%d.in", cg_id);
305 		else
306 			sprintf(fname, "hbm.%d.out", cg_id);
307 		fout = fopen(fname, "w");
308 		fprintf(fout, "id:%d\n", cg_id);
309 		fprintf(fout, "ERROR: Could not lookup queue_stats\n");
310 	} else if (stats_flag && qstats.lastPacketTime >
311 		   qstats.firstPacketTime) {
312 		long long delta_us = (qstats.lastPacketTime -
313 				      qstats.firstPacketTime)/1000;
314 		unsigned int rate_mbps = ((qstats.bytes_total -
315 					   qstats.bytes_dropped) * 8 /
316 					  delta_us);
317 		double percent_pkts, percent_bytes;
318 		char fname[100];
319 		FILE *fout;
320 		int k;
321 		static const char *returnValNames[] = {
322 			"DROP_PKT",
323 			"ALLOW_PKT",
324 			"DROP_PKT_CWR",
325 			"ALLOW_PKT_CWR"
326 		};
327 #define RET_VAL_COUNT 4
328 
329 // Future support of ingress
330 //		if (!outFlag)
331 //			sprintf(fname, "hbm.%d.in", cg_id);
332 //		else
333 		sprintf(fname, "hbm.%d.out", cg_id);
334 		fout = fopen(fname, "w");
335 		fprintf(fout, "id:%d\n", cg_id);
336 		fprintf(fout, "rate_mbps:%d\n", rate_mbps);
337 		fprintf(fout, "duration:%.1f secs\n",
338 			(qstats.lastPacketTime - qstats.firstPacketTime) /
339 			1000000000.0);
340 		fprintf(fout, "packets:%d\n", (int)qstats.pkts_total);
341 		fprintf(fout, "bytes_MB:%d\n", (int)(qstats.bytes_total /
342 						     1000000));
343 		fprintf(fout, "pkts_dropped:%d\n", (int)qstats.pkts_dropped);
344 		fprintf(fout, "bytes_dropped_MB:%d\n",
345 			(int)(qstats.bytes_dropped /
346 						       1000000));
347 		// Marked Pkts and Bytes
348 		percent_pkts = (qstats.pkts_marked * 100.0) /
349 			(qstats.pkts_total + 1);
350 		percent_bytes = (qstats.bytes_marked * 100.0) /
351 			(qstats.bytes_total + 1);
352 		fprintf(fout, "pkts_marked_percent:%6.2f\n", percent_pkts);
353 		fprintf(fout, "bytes_marked_percent:%6.2f\n", percent_bytes);
354 
355 		// Dropped Pkts and Bytes
356 		percent_pkts = (qstats.pkts_dropped * 100.0) /
357 			(qstats.pkts_total + 1);
358 		percent_bytes = (qstats.bytes_dropped * 100.0) /
359 			(qstats.bytes_total + 1);
360 		fprintf(fout, "pkts_dropped_percent:%6.2f\n", percent_pkts);
361 		fprintf(fout, "bytes_dropped_percent:%6.2f\n", percent_bytes);
362 
363 		// ECN CE markings
364 		percent_pkts = (qstats.pkts_ecn_ce * 100.0) /
365 			(qstats.pkts_total + 1);
366 		fprintf(fout, "pkts_ecn_ce:%6.2f (%d)\n", percent_pkts,
367 			(int)qstats.pkts_ecn_ce);
368 
369 		// Average cwnd
370 		fprintf(fout, "avg cwnd:%d\n",
371 			(int)(qstats.sum_cwnd / (qstats.sum_cwnd_cnt + 1)));
372 		// Average rtt
373 		fprintf(fout, "avg rtt:%d\n",
374 			(int)(qstats.sum_rtt / (qstats.pkts_total + 1)));
375 		// Average credit
376 		if (edt_flag)
377 			fprintf(fout, "avg credit_ms:%.03f\n",
378 				(qstats.sum_credit /
379 				 (qstats.pkts_total + 1.0)) / 1000000.0);
380 		else
381 			fprintf(fout, "avg credit:%d\n",
382 				(int)(qstats.sum_credit /
383 				      (1500 * ((int)qstats.pkts_total ) + 1)));
384 
385 		// Return values stats
386 		for (k = 0; k < RET_VAL_COUNT; k++) {
387 			percent_pkts = (qstats.returnValCount[k] * 100.0) /
388 				(qstats.pkts_total + 1);
389 			fprintf(fout, "%s:%6.2f (%d)\n", returnValNames[k],
390 				percent_pkts, (int)qstats.returnValCount[k]);
391 		}
392 		fclose(fout);
393 	}
394 
395 	if (debugFlag)
396 		read_trace_pipe2();
397 	return rc;
398 err:
399 	rc = 1;
400 
401 	if (cg1)
402 		close(cg1);
403 	cleanup_cgroup_environment();
404 
405 	return rc;
406 }
407 
408 static void Usage(void)
409 {
410 	printf("This program loads a cgroup skb BPF program to enforce\n"
411 	       "cgroup output (egress) bandwidth limits.\n\n"
412 	       "USAGE: hbm [-o] [-d]  [-l] [-n <id>] [--no_cn] [-r <rate>]\n"
413 	       "           [-s] [-t <secs>] [-w] [-h] [prog]\n"
414 	       "  Where:\n"
415 	       "    -o         indicates egress direction (default)\n"
416 	       "    -d         print BPF trace debug buffer\n"
417 	       "    --edt      use fq's Earliest Departure Time\n"
418 	       "    -l         also limit flows using loopback\n"
419 	       "    -n <#>     to create cgroup \"/hbm#\" and attach prog\n"
420 	       "               Default is /hbm1\n"
421 	       "    --no_cn    disable CN notifications\n"
422 	       "    -r <rate>  Rate in Mbps\n"
423 	       "    -s         Update HBM stats\n"
424 	       "    -t <time>  Exit after specified seconds (default is 0)\n"
425 	       "    -w	       Work conserving flag. cgroup can increase\n"
426 	       "               bandwidth beyond the rate limit specified\n"
427 	       "               while there is available bandwidth. Current\n"
428 	       "               implementation assumes there is only eth0\n"
429 	       "               but can be extended to support multiple NICs\n"
430 	       "    -h         print this info\n"
431 	       "    prog       BPF program file name. Name defaults to\n"
432 	       "                 hbm_out_kern.o\n");
433 }
434 
435 int main(int argc, char **argv)
436 {
437 	char *prog = "hbm_out_kern.o";
438 	int  k;
439 	int cg_id = 1;
440 	char *optstring = "iodln:r:st:wh";
441 	struct option loptions[] = {
442 		{"no_cn", 0, NULL, 1},
443 		{"edt", 0, NULL, 2},
444 		{NULL, 0, NULL, 0}
445 	};
446 
447 	while ((k = getopt_long(argc, argv, optstring, loptions, NULL)) != -1) {
448 		switch (k) {
449 		case 1:
450 			no_cn_flag = true;
451 			break;
452 		case 2:
453 			prog = "hbm_edt_kern.o";
454 			edt_flag = true;
455 			break;
456 		case'o':
457 			break;
458 		case 'd':
459 			debugFlag = true;
460 			break;
461 		case 'l':
462 			loopback_flag = true;
463 			break;
464 		case 'n':
465 			cg_id = atoi(optarg);
466 			break;
467 		case 'r':
468 			minRate = atoi(optarg) * 1.024;
469 			rate = minRate;
470 			break;
471 		case 's':
472 			stats_flag = true;
473 			break;
474 		case 't':
475 			dur = atoi(optarg);
476 			break;
477 		case 'w':
478 			work_conserving_flag = true;
479 			break;
480 		case '?':
481 			if (optopt == 'n' || optopt == 'r' || optopt == 't')
482 				fprintf(stderr,
483 					"Option -%c requires an argument.\n\n",
484 					optopt);
485 		case 'h':
486 			// fallthrough
487 		default:
488 			Usage();
489 			return 0;
490 		}
491 	}
492 
493 	if (optind < argc)
494 		prog = argv[optind];
495 	printf("HBM prog: %s\n", prog != NULL ? prog : "NULL");
496 
497 	return run_bpf_prog(prog, cg_id);
498 }
499