| // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) |
| // Copyright (c) 2019 Facebook |
| // |
| // Based on runqslower(8) from BCC by Ivan Babrou. |
| // 11-Feb-2020 Andrii Nakryiko Created this. |
| #include <argp.h> |
| #include <signal.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <time.h> |
| #include <bpf/libbpf.h> |
| #include <bpf/bpf.h> |
| #include "runqslower.h" |
| #include "runqslower.skel.h" |
| #include "trace_helpers.h" |
| |
| static volatile sig_atomic_t exiting = 0; |
| |
| struct env { |
| pid_t pid; |
| pid_t tid; |
| __u64 min_us; |
| bool previous; |
| bool verbose; |
| } env = { |
| .min_us = 10000, |
| }; |
| |
| const char *argp_program_version = "runqslower 0.1"; |
| const char *argp_program_bug_address = |
| "https://github.com/iovisor/bcc/tree/master/libbpf-tools"; |
| const char argp_program_doc[] = |
| "Trace high run queue latency.\n" |
| "\n" |
| "USAGE: runqslower [--help] [-p PID] [-t TID] [-P] [min_us]\n" |
| "\n" |
| "EXAMPLES:\n" |
| " runqslower # trace latency higher than 10000 us (default)\n" |
| " runqslower 1000 # trace latency higher than 1000 us\n" |
| " runqslower -p 123 # trace pid 123\n" |
| " runqslower -t 123 # trace tid 123 (use for threads only)\n" |
| " runqslower -P # also show previous task name and TID\n"; |
| |
| static const struct argp_option opts[] = { |
| { "pid", 'p', "PID", 0, "Process PID to trace"}, |
| { "tid", 't', "TID", 0, "Thread TID to trace"}, |
| { "verbose", 'v', NULL, 0, "Verbose debug output" }, |
| { "previous", 'P', NULL, 0, "also show previous task name and TID" }, |
| { NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help" }, |
| {}, |
| }; |
| |
| static error_t parse_arg(int key, char *arg, struct argp_state *state) |
| { |
| static int pos_args; |
| int pid; |
| long long min_us; |
| |
| switch (key) { |
| case 'h': |
| argp_state_help(state, stderr, ARGP_HELP_STD_HELP); |
| break; |
| case 'v': |
| env.verbose = true; |
| break; |
| case 'P': |
| env.previous = true; |
| break; |
| case 'p': |
| errno = 0; |
| pid = strtol(arg, NULL, 10); |
| if (errno || pid <= 0) { |
| fprintf(stderr, "Invalid PID: %s\n", arg); |
| argp_usage(state); |
| } |
| env.pid = pid; |
| break; |
| case 't': |
| errno = 0; |
| pid = strtol(arg, NULL, 10); |
| if (errno || pid <= 0) { |
| fprintf(stderr, "Invalid TID: %s\n", arg); |
| argp_usage(state); |
| } |
| env.tid = pid; |
| break; |
| case ARGP_KEY_ARG: |
| if (pos_args++) { |
| fprintf(stderr, |
| "Unrecognized positional argument: %s\n", arg); |
| argp_usage(state); |
| } |
| errno = 0; |
| min_us = strtoll(arg, NULL, 10); |
| if (errno || min_us <= 0) { |
| fprintf(stderr, "Invalid delay (in us): %s\n", arg); |
| argp_usage(state); |
| } |
| env.min_us = min_us; |
| break; |
| default: |
| return ARGP_ERR_UNKNOWN; |
| } |
| return 0; |
| } |
| |
| static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args) |
| { |
| if (level == LIBBPF_DEBUG && !env.verbose) |
| return 0; |
| return vfprintf(stderr, format, args); |
| } |
| |
| static void sig_int(int signo) |
| { |
| exiting = 1; |
| } |
| |
| void handle_event(void *ctx, int cpu, void *data, __u32 data_sz) |
| { |
| const struct event *e = data; |
| struct tm *tm; |
| char ts[32]; |
| time_t t; |
| |
| time(&t); |
| tm = localtime(&t); |
| strftime(ts, sizeof(ts), "%H:%M:%S", tm); |
| if (env.previous) |
| printf("%-8s %-16s %-6d %14llu %-16s %-6d\n", ts, e->task, e->pid, e->delta_us, e->prev_task, e->prev_pid); |
| else |
| printf("%-8s %-16s %-6d %14llu\n", ts, e->task, e->pid, e->delta_us); |
| } |
| |
| void handle_lost_events(void *ctx, int cpu, __u64 lost_cnt) |
| { |
| printf("Lost %llu events on CPU #%d!\n", lost_cnt, cpu); |
| } |
| |
| int main(int argc, char **argv) |
| { |
| static const struct argp argp = { |
| .options = opts, |
| .parser = parse_arg, |
| .doc = argp_program_doc, |
| }; |
| struct perf_buffer *pb = NULL; |
| struct runqslower_bpf *obj; |
| int err; |
| |
| err = argp_parse(&argp, argc, argv, 0, NULL, NULL); |
| if (err) |
| return err; |
| |
| libbpf_set_strict_mode(LIBBPF_STRICT_ALL); |
| libbpf_set_print(libbpf_print_fn); |
| |
| obj = runqslower_bpf__open(); |
| if (!obj) { |
| fprintf(stderr, "failed to open BPF object\n"); |
| return 1; |
| } |
| |
| /* initialize global data (filtering options) */ |
| obj->rodata->targ_tgid = env.pid; |
| obj->rodata->targ_pid = env.tid; |
| obj->rodata->min_us = env.min_us; |
| |
| err = runqslower_bpf__load(obj); |
| if (err) { |
| fprintf(stderr, "failed to load BPF object: %d\n", err); |
| goto cleanup; |
| } |
| |
| err = runqslower_bpf__attach(obj); |
| if (err) { |
| fprintf(stderr, "failed to attach BPF programs\n"); |
| goto cleanup; |
| } |
| |
| printf("Tracing run queue latency higher than %llu us\n", env.min_us); |
| if (env.previous) |
| printf("%-8s %-16s %-6s %14s %-16s %-6s\n", "TIME", "COMM", "TID", "LAT(us)", "PREV COMM", "PREV TID"); |
| else |
| printf("%-8s %-16s %-6s %14s\n", "TIME", "COMM", "TID", "LAT(us)"); |
| |
| pb = perf_buffer__new(bpf_map__fd(obj->maps.events), 64, |
| handle_event, handle_lost_events, NULL, NULL); |
| if (!pb) { |
| err = -errno; |
| fprintf(stderr, "failed to open perf buffer: %d\n", err); |
| goto cleanup; |
| } |
| |
| if (signal(SIGINT, sig_int) == SIG_ERR) { |
| fprintf(stderr, "can't set signal handler: %s\n", strerror(errno)); |
| err = 1; |
| goto cleanup; |
| } |
| |
| while (!exiting) { |
| err = perf_buffer__poll(pb, 100); |
| if (err < 0 && err != -EINTR) { |
| fprintf(stderr, "error polling perf buffer: %s\n", strerror(-err)); |
| goto cleanup; |
| } |
| /* reset err to return 0 if exiting */ |
| err = 0; |
| } |
| |
| cleanup: |
| perf_buffer__free(pb); |
| runqslower_bpf__destroy(obj); |
| |
| return err != 0; |
| } |