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![Daniel T. Lee](/assets/img/avatar_default.png)
Currently, the kprobe BPF program attachment method for bpf_load is quite old. The implementation of bpf_load "directly" controls and manages(create, delete) the kprobe events of DEBUGFS. On the other hand, using using the libbpf automatically manages the kprobe event. (under bpf_link interface) By calling bpf_program__attach(_kprobe) in libbpf, the corresponding kprobe is created and the BPF program will be attached to this kprobe. To remove this, by simply invoking bpf_link__destroy will clean up the event. This commit refactors kprobe tracing programs (tracex{1~7}_user.c) with libbpf using bpf_link interface and bpf_program__attach. tracex2_kern.c, which tracks system calls (sys_*), has been modified to append prefix depending on architecture. Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200516040608.1377876-3-danieltimlee@gmail.com
190 lines
3.8 KiB
C
190 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <unistd.h>
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#include <stdbool.h>
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#include <string.h>
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#include <sys/resource.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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#include "bpf_util.h"
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#define SLOTS 100
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static void clear_stats(int fd)
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{
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unsigned int nr_cpus = bpf_num_possible_cpus();
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__u64 values[nr_cpus];
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__u32 key;
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memset(values, 0, sizeof(values));
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for (key = 0; key < SLOTS; key++)
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bpf_map_update_elem(fd, &key, values, BPF_ANY);
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}
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const char *color[] = {
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"\033[48;5;255m",
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"\033[48;5;252m",
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"\033[48;5;250m",
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"\033[48;5;248m",
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"\033[48;5;246m",
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"\033[48;5;244m",
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"\033[48;5;242m",
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"\033[48;5;240m",
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"\033[48;5;238m",
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"\033[48;5;236m",
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"\033[48;5;234m",
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"\033[48;5;232m",
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};
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const int num_colors = ARRAY_SIZE(color);
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const char nocolor[] = "\033[00m";
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const char *sym[] = {
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" ",
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" ",
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".",
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".",
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"*",
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"*",
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"o",
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"o",
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"O",
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"O",
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"#",
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"#",
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};
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bool full_range = false;
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bool text_only = false;
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static void print_banner(void)
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{
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if (full_range)
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printf("|1ns |10ns |100ns |1us |10us |100us"
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" |1ms |10ms |100ms |1s |10s\n");
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else
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printf("|1us |10us |100us |1ms |10ms "
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"|100ms |1s |10s\n");
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}
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static void print_hist(int fd)
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{
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unsigned int nr_cpus = bpf_num_possible_cpus();
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__u64 total_events = 0;
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long values[nr_cpus];
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__u64 max_cnt = 0;
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__u64 cnt[SLOTS];
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__u64 value;
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__u32 key;
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int i;
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for (key = 0; key < SLOTS; key++) {
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bpf_map_lookup_elem(fd, &key, values);
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value = 0;
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for (i = 0; i < nr_cpus; i++)
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value += values[i];
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cnt[key] = value;
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total_events += value;
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if (value > max_cnt)
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max_cnt = value;
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}
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clear_stats(fd);
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for (key = full_range ? 0 : 29; key < SLOTS; key++) {
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int c = num_colors * cnt[key] / (max_cnt + 1);
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if (text_only)
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printf("%s", sym[c]);
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else
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printf("%s %s", color[c], nocolor);
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}
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printf(" # %lld\n", total_events);
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}
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int main(int ac, char **argv)
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{
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struct rlimit r = {1024*1024, RLIM_INFINITY};
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struct bpf_link *links[2];
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struct bpf_program *prog;
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struct bpf_object *obj;
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char filename[256];
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int map_fd, i, j = 0;
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for (i = 1; i < ac; i++) {
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if (strcmp(argv[i], "-a") == 0) {
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full_range = true;
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} else if (strcmp(argv[i], "-t") == 0) {
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text_only = true;
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} else if (strcmp(argv[i], "-h") == 0) {
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printf("Usage:\n"
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" -a display wider latency range\n"
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" -t text only\n");
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return 1;
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}
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}
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if (setrlimit(RLIMIT_MEMLOCK, &r)) {
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perror("setrlimit(RLIMIT_MEMLOCK)");
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return 1;
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}
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snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
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obj = bpf_object__open_file(filename, NULL);
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if (libbpf_get_error(obj)) {
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fprintf(stderr, "ERROR: opening BPF object file failed\n");
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return 0;
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}
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/* load BPF program */
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if (bpf_object__load(obj)) {
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fprintf(stderr, "ERROR: loading BPF object file failed\n");
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goto cleanup;
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}
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map_fd = bpf_object__find_map_fd_by_name(obj, "lat_map");
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if (map_fd < 0) {
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fprintf(stderr, "ERROR: finding a map in obj file failed\n");
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goto cleanup;
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}
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bpf_object__for_each_program(prog, obj) {
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links[j] = bpf_program__attach(prog);
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if (libbpf_get_error(links[j])) {
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fprintf(stderr, "ERROR: bpf_program__attach failed\n");
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links[j] = NULL;
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goto cleanup;
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}
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j++;
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}
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printf(" heatmap of IO latency\n");
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if (text_only)
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printf(" %s", sym[num_colors - 1]);
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else
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printf(" %s %s", color[num_colors - 1], nocolor);
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printf(" - many events with this latency\n");
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if (text_only)
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printf(" %s", sym[0]);
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else
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printf(" %s %s", color[0], nocolor);
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printf(" - few events\n");
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for (i = 0; ; i++) {
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if (i % 20 == 0)
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print_banner();
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print_hist(map_fd);
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sleep(2);
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}
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cleanup:
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for (j--; j >= 0; j--)
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bpf_link__destroy(links[j]);
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bpf_object__close(obj);
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return 0;
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}
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