linux/samples/bpf/hbm.c
Daniel T. Lee c5815ac7e2 samples: bpf: Refactor hbm program with libbpf
This commit refactors the existing cgroup programs with libbpf
bpf loader. Since bpf_program__attach doesn't support cgroup program
attachment, this explicitly attaches cgroup bpf program with
bpf_program__attach_cgroup(bpf_prog, cg1).

Also, to change attach_type of bpf program, this uses libbpf's
bpf_program__set_expected_attach_type helper to switch EGRESS to
INGRESS. To keep bpf program attached to the cgroup hierarchy even
after the exit, this commit uses the BPF_LINK_PINNING to pin the link
attachment even after it is closed.

Besides, this program was broken due to the typo of BPF MAP definition.
But this commit solves the problem by fixing this from 'queue_stats' map
struct hvm_queue_stats -> hbm_queue_stats.

Fixes: 36b5d47113 ("selftests/bpf: samples/bpf: Split off legacy stuff from bpf_helpers.h")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201124090310.24374-2-danieltimlee@gmail.com
2020-11-26 19:33:35 -08:00

506 lines
13 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* Example program for Host Bandwidth Managment
*
* This program loads a cgroup skb BPF program to enforce cgroup output
* (egress) or input (ingress) bandwidth limits.
*
* USAGE: hbm [-d] [-l] [-n <id>] [-r <rate>] [-s] [-t <secs>] [-w] [-h] [prog]
* Where:
* -d Print BPF trace debug buffer
* -l Also limit flows doing loopback
* -n <#> To create cgroup \"/hbm#\" and attach prog
* Default is /hbm1
* --no_cn Do not return cn notifications
* -r <rate> Rate limit in Mbps
* -s Get HBM stats (marked, dropped, etc.)
* -t <time> Exit after specified seconds (default is 0)
* -w Work conserving flag. cgroup can increase its bandwidth
* beyond the rate limit specified while there is available
* bandwidth. Current implementation assumes there is only
* NIC (eth0), but can be extended to support multiple NICs.
* Currrently only supported for egress.
* -h Print this info
* prog BPF program file name. Name defaults to hbm_out_kern.o
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/unistd.h>
#include <linux/compiler.h>
#include <linux/bpf.h>
#include <bpf/bpf.h>
#include <getopt.h>
#include "bpf_rlimit.h"
#include "cgroup_helpers.h"
#include "hbm.h"
#include "bpf_util.h"
#include <bpf/libbpf.h>
bool outFlag = true;
int minRate = 1000; /* cgroup rate limit in Mbps */
int rate = 1000; /* can grow if rate conserving is enabled */
int dur = 1;
bool stats_flag;
bool loopback_flag;
bool debugFlag;
bool work_conserving_flag;
bool no_cn_flag;
bool edt_flag;
static void Usage(void);
static void read_trace_pipe2(void);
static void do_error(char *msg, bool errno_flag);
#define DEBUGFS "/sys/kernel/debug/tracing/"
static struct bpf_program *bpf_prog;
static struct bpf_object *obj;
static int queue_stats_fd;
static void read_trace_pipe2(void)
{
int trace_fd;
FILE *outf;
char *outFname = "hbm_out.log";
trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
if (trace_fd < 0) {
printf("Error opening trace_pipe\n");
return;
}
// Future support of ingress
// if (!outFlag)
// outFname = "hbm_in.log";
outf = fopen(outFname, "w");
if (outf == NULL)
printf("Error creating %s\n", outFname);
while (1) {
static char buf[4097];
ssize_t sz;
sz = read(trace_fd, buf, sizeof(buf) - 1);
if (sz > 0) {
buf[sz] = 0;
puts(buf);
if (outf != NULL) {
fprintf(outf, "%s\n", buf);
fflush(outf);
}
}
}
}
static void do_error(char *msg, bool errno_flag)
{
if (errno_flag)
printf("ERROR: %s, errno: %d\n", msg, errno);
else
printf("ERROR: %s\n", msg);
exit(1);
}
static int prog_load(char *prog)
{
obj = bpf_object__open_file(prog, NULL);
if (libbpf_get_error(obj)) {
printf("ERROR: opening BPF object file failed\n");
return 1;
}
/* load BPF program */
if (bpf_object__load(obj)) {
printf("ERROR: loading BPF object file failed\n");
goto err;
}
bpf_prog = bpf_object__find_program_by_title(obj, "cgroup_skb/egress");
if (!bpf_prog) {
printf("ERROR: finding a prog in obj file failed\n");
goto err;
}
queue_stats_fd = bpf_object__find_map_fd_by_name(obj, "queue_stats");
if (queue_stats_fd < 0) {
printf("ERROR: finding a map in obj file failed\n");
goto err;
}
return 0;
err:
bpf_object__close(obj);
return 1;
}
static int run_bpf_prog(char *prog, int cg_id)
{
struct hbm_queue_stats qstats = {0};
char cg_dir[100], cg_pin_path[100];
struct bpf_link *link = NULL;
int key = 0;
int cg1 = 0;
int rc = 0;
sprintf(cg_dir, "/hbm%d", cg_id);
rc = prog_load(prog);
if (rc != 0)
return rc;
if (setup_cgroup_environment()) {
printf("ERROR: setting cgroup environment\n");
goto err;
}
cg1 = create_and_get_cgroup(cg_dir);
if (!cg1) {
printf("ERROR: create_and_get_cgroup\n");
goto err;
}
if (join_cgroup(cg_dir)) {
printf("ERROR: join_cgroup\n");
goto err;
}
qstats.rate = rate;
qstats.stats = stats_flag ? 1 : 0;
qstats.loopback = loopback_flag ? 1 : 0;
qstats.no_cn = no_cn_flag ? 1 : 0;
if (bpf_map_update_elem(queue_stats_fd, &key, &qstats, BPF_ANY)) {
printf("ERROR: Could not update map element\n");
goto err;
}
if (!outFlag)
bpf_program__set_expected_attach_type(bpf_prog, BPF_CGROUP_INET_INGRESS);
link = bpf_program__attach_cgroup(bpf_prog, cg1);
if (libbpf_get_error(link)) {
fprintf(stderr, "ERROR: bpf_program__attach_cgroup failed\n");
goto err;
}
sprintf(cg_pin_path, "/sys/fs/bpf/hbm%d", cg_id);
rc = bpf_link__pin(link, cg_pin_path);
if (rc < 0) {
printf("ERROR: bpf_link__pin failed: %d\n", rc);
goto err;
}
if (work_conserving_flag) {
struct timeval t0, t_last, t_new;
FILE *fin;
unsigned long long last_eth_tx_bytes, new_eth_tx_bytes;
signed long long last_cg_tx_bytes, new_cg_tx_bytes;
signed long long delta_time, delta_bytes, delta_rate;
int delta_ms;
#define DELTA_RATE_CHECK 10000 /* in us */
#define RATE_THRESHOLD 9500000000 /* 9.5 Gbps */
bpf_map_lookup_elem(queue_stats_fd, &key, &qstats);
if (gettimeofday(&t0, NULL) < 0)
do_error("gettimeofday failed", true);
t_last = t0;
fin = fopen("/sys/class/net/eth0/statistics/tx_bytes", "r");
if (fscanf(fin, "%llu", &last_eth_tx_bytes) != 1)
do_error("fscanf fails", false);
fclose(fin);
last_cg_tx_bytes = qstats.bytes_total;
while (true) {
usleep(DELTA_RATE_CHECK);
if (gettimeofday(&t_new, NULL) < 0)
do_error("gettimeofday failed", true);
delta_ms = (t_new.tv_sec - t0.tv_sec) * 1000 +
(t_new.tv_usec - t0.tv_usec)/1000;
if (delta_ms > dur * 1000)
break;
delta_time = (t_new.tv_sec - t_last.tv_sec) * 1000000 +
(t_new.tv_usec - t_last.tv_usec);
if (delta_time == 0)
continue;
t_last = t_new;
fin = fopen("/sys/class/net/eth0/statistics/tx_bytes",
"r");
if (fscanf(fin, "%llu", &new_eth_tx_bytes) != 1)
do_error("fscanf fails", false);
fclose(fin);
printf(" new_eth_tx_bytes:%llu\n",
new_eth_tx_bytes);
bpf_map_lookup_elem(queue_stats_fd, &key, &qstats);
new_cg_tx_bytes = qstats.bytes_total;
delta_bytes = new_eth_tx_bytes - last_eth_tx_bytes;
last_eth_tx_bytes = new_eth_tx_bytes;
delta_rate = (delta_bytes * 8000000) / delta_time;
printf("%5d - eth_rate:%.1fGbps cg_rate:%.3fGbps",
delta_ms, delta_rate/1000000000.0,
rate/1000.0);
if (delta_rate < RATE_THRESHOLD) {
/* can increase cgroup rate limit, but first
* check if we are using the current limit.
* Currently increasing by 6.25%, unknown
* if that is the optimal rate.
*/
int rate_diff100;
delta_bytes = new_cg_tx_bytes -
last_cg_tx_bytes;
last_cg_tx_bytes = new_cg_tx_bytes;
delta_rate = (delta_bytes * 8000000) /
delta_time;
printf(" rate:%.3fGbps",
delta_rate/1000000000.0);
rate_diff100 = (((long long)rate)*1000000 -
delta_rate) * 100 /
(((long long) rate) * 1000000);
printf(" rdiff:%d", rate_diff100);
if (rate_diff100 <= 3) {
rate += (rate >> 4);
if (rate > RATE_THRESHOLD / 1000000)
rate = RATE_THRESHOLD / 1000000;
qstats.rate = rate;
printf(" INC\n");
} else {
printf("\n");
}
} else {
/* Need to decrease cgroup rate limit.
* Currently decreasing by 12.5%, unknown
* if that is optimal
*/
printf(" DEC\n");
rate -= (rate >> 3);
if (rate < minRate)
rate = minRate;
qstats.rate = rate;
}
if (bpf_map_update_elem(queue_stats_fd, &key, &qstats, BPF_ANY))
do_error("update map element fails", false);
}
} else {
sleep(dur);
}
// Get stats!
if (stats_flag && bpf_map_lookup_elem(queue_stats_fd, &key, &qstats)) {
char fname[100];
FILE *fout;
if (!outFlag)
sprintf(fname, "hbm.%d.in", cg_id);
else
sprintf(fname, "hbm.%d.out", cg_id);
fout = fopen(fname, "w");
fprintf(fout, "id:%d\n", cg_id);
fprintf(fout, "ERROR: Could not lookup queue_stats\n");
} else if (stats_flag && qstats.lastPacketTime >
qstats.firstPacketTime) {
long long delta_us = (qstats.lastPacketTime -
qstats.firstPacketTime)/1000;
unsigned int rate_mbps = ((qstats.bytes_total -
qstats.bytes_dropped) * 8 /
delta_us);
double percent_pkts, percent_bytes;
char fname[100];
FILE *fout;
int k;
static const char *returnValNames[] = {
"DROP_PKT",
"ALLOW_PKT",
"DROP_PKT_CWR",
"ALLOW_PKT_CWR"
};
#define RET_VAL_COUNT 4
// Future support of ingress
// if (!outFlag)
// sprintf(fname, "hbm.%d.in", cg_id);
// else
sprintf(fname, "hbm.%d.out", cg_id);
fout = fopen(fname, "w");
fprintf(fout, "id:%d\n", cg_id);
fprintf(fout, "rate_mbps:%d\n", rate_mbps);
fprintf(fout, "duration:%.1f secs\n",
(qstats.lastPacketTime - qstats.firstPacketTime) /
1000000000.0);
fprintf(fout, "packets:%d\n", (int)qstats.pkts_total);
fprintf(fout, "bytes_MB:%d\n", (int)(qstats.bytes_total /
1000000));
fprintf(fout, "pkts_dropped:%d\n", (int)qstats.pkts_dropped);
fprintf(fout, "bytes_dropped_MB:%d\n",
(int)(qstats.bytes_dropped /
1000000));
// Marked Pkts and Bytes
percent_pkts = (qstats.pkts_marked * 100.0) /
(qstats.pkts_total + 1);
percent_bytes = (qstats.bytes_marked * 100.0) /
(qstats.bytes_total + 1);
fprintf(fout, "pkts_marked_percent:%6.2f\n", percent_pkts);
fprintf(fout, "bytes_marked_percent:%6.2f\n", percent_bytes);
// Dropped Pkts and Bytes
percent_pkts = (qstats.pkts_dropped * 100.0) /
(qstats.pkts_total + 1);
percent_bytes = (qstats.bytes_dropped * 100.0) /
(qstats.bytes_total + 1);
fprintf(fout, "pkts_dropped_percent:%6.2f\n", percent_pkts);
fprintf(fout, "bytes_dropped_percent:%6.2f\n", percent_bytes);
// ECN CE markings
percent_pkts = (qstats.pkts_ecn_ce * 100.0) /
(qstats.pkts_total + 1);
fprintf(fout, "pkts_ecn_ce:%6.2f (%d)\n", percent_pkts,
(int)qstats.pkts_ecn_ce);
// Average cwnd
fprintf(fout, "avg cwnd:%d\n",
(int)(qstats.sum_cwnd / (qstats.sum_cwnd_cnt + 1)));
// Average rtt
fprintf(fout, "avg rtt:%d\n",
(int)(qstats.sum_rtt / (qstats.pkts_total + 1)));
// Average credit
if (edt_flag)
fprintf(fout, "avg credit_ms:%.03f\n",
(qstats.sum_credit /
(qstats.pkts_total + 1.0)) / 1000000.0);
else
fprintf(fout, "avg credit:%d\n",
(int)(qstats.sum_credit /
(1500 * ((int)qstats.pkts_total ) + 1)));
// Return values stats
for (k = 0; k < RET_VAL_COUNT; k++) {
percent_pkts = (qstats.returnValCount[k] * 100.0) /
(qstats.pkts_total + 1);
fprintf(fout, "%s:%6.2f (%d)\n", returnValNames[k],
percent_pkts, (int)qstats.returnValCount[k]);
}
fclose(fout);
}
if (debugFlag)
read_trace_pipe2();
goto cleanup;
err:
rc = 1;
cleanup:
bpf_link__destroy(link);
bpf_object__close(obj);
if (cg1 != -1)
close(cg1);
if (rc != 0)
cleanup_cgroup_environment();
return rc;
}
static void Usage(void)
{
printf("This program loads a cgroup skb BPF program to enforce\n"
"cgroup output (egress) bandwidth limits.\n\n"
"USAGE: hbm [-o] [-d] [-l] [-n <id>] [--no_cn] [-r <rate>]\n"
" [-s] [-t <secs>] [-w] [-h] [prog]\n"
" Where:\n"
" -o indicates egress direction (default)\n"
" -d print BPF trace debug buffer\n"
" --edt use fq's Earliest Departure Time\n"
" -l also limit flows using loopback\n"
" -n <#> to create cgroup \"/hbm#\" and attach prog\n"
" Default is /hbm1\n"
" --no_cn disable CN notifications\n"
" -r <rate> Rate in Mbps\n"
" -s Update HBM stats\n"
" -t <time> Exit after specified seconds (default is 0)\n"
" -w Work conserving flag. cgroup can increase\n"
" bandwidth beyond the rate limit specified\n"
" while there is available bandwidth. Current\n"
" implementation assumes there is only eth0\n"
" but can be extended to support multiple NICs\n"
" -h print this info\n"
" prog BPF program file name. Name defaults to\n"
" hbm_out_kern.o\n");
}
int main(int argc, char **argv)
{
char *prog = "hbm_out_kern.o";
int k;
int cg_id = 1;
char *optstring = "iodln:r:st:wh";
struct option loptions[] = {
{"no_cn", 0, NULL, 1},
{"edt", 0, NULL, 2},
{NULL, 0, NULL, 0}
};
while ((k = getopt_long(argc, argv, optstring, loptions, NULL)) != -1) {
switch (k) {
case 1:
no_cn_flag = true;
break;
case 2:
prog = "hbm_edt_kern.o";
edt_flag = true;
break;
case'o':
break;
case 'd':
debugFlag = true;
break;
case 'l':
loopback_flag = true;
break;
case 'n':
cg_id = atoi(optarg);
break;
case 'r':
minRate = atoi(optarg) * 1.024;
rate = minRate;
break;
case 's':
stats_flag = true;
break;
case 't':
dur = atoi(optarg);
break;
case 'w':
work_conserving_flag = true;
break;
case '?':
if (optopt == 'n' || optopt == 'r' || optopt == 't')
fprintf(stderr,
"Option -%c requires an argument.\n\n",
optopt);
case 'h':
__fallthrough;
default:
Usage();
return 0;
}
}
if (optind < argc)
prog = argv[optind];
printf("HBM prog: %s\n", prog != NULL ? prog : "NULL");
return run_bpf_prog(prog, cg_id);
}