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-rw-r--r--tools/bpf/runqslower/runqslower.c187
1 files changed, 187 insertions, 0 deletions
diff --git a/tools/bpf/runqslower/runqslower.c b/tools/bpf/runqslower/runqslower.c
new file mode 100644
index 000000000..d89715844
--- /dev/null
+++ b/tools/bpf/runqslower/runqslower.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+// Copyright (c) 2019 Facebook
+#include <argp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <time.h>
+#include <bpf/libbpf.h>
+#include <bpf/bpf.h>
+#include "runqslower.h"
+#include "runqslower.skel.h"
+
+struct env {
+ pid_t pid;
+ __u64 min_us;
+ bool verbose;
+} env = {
+ .min_us = 10000,
+};
+
+const char *argp_program_version = "runqslower 0.1";
+const char *argp_program_bug_address = "<bpf@vger.kernel.org>";
+const char argp_program_doc[] =
+"runqslower Trace long process scheduling delays.\n"
+" For Linux, uses eBPF, BPF CO-RE, libbpf, BTF.\n"
+"\n"
+"This script traces high scheduling delays between tasks being\n"
+"ready to run and them running on CPU after that.\n"
+"\n"
+"USAGE: runqslower [-p PID] [min_us]\n"
+"\n"
+"EXAMPLES:\n"
+" runqslower # trace run queue latency higher than 10000 us (default)\n"
+" runqslower 1000 # trace run queue latency higher than 1000 us\n"
+" runqslower -p 123 # trace pid 123 only\n";
+
+static const struct argp_option opts[] = {
+ { "pid", 'p', "PID", 0, "Process PID to trace"},
+ { "verbose", 'v', NULL, 0, "Verbose debug output" },
+ {},
+};
+
+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 'v':
+ env.verbose = 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 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;
+}
+
+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 int bump_memlock_rlimit(void)
+{
+ struct rlimit rlim_new = {
+ .rlim_cur = RLIM_INFINITY,
+ .rlim_max = RLIM_INFINITY,
+ };
+
+ return setrlimit(RLIMIT_MEMLOCK, &rlim_new);
+}
+
+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);
+ 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_opts pb_opts;
+ 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_print(libbpf_print_fn);
+
+ err = bump_memlock_rlimit();
+ if (err) {
+ fprintf(stderr, "failed to increase rlimit: %d", err);
+ return 1;
+ }
+
+ obj = runqslower_bpf__open();
+ if (!obj) {
+ fprintf(stderr, "failed to open and/or load BPF object\n");
+ return 1;
+ }
+
+ /* initialize global data (filtering options) */
+ obj->rodata->targ_pid = env.pid;
+ 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);
+ printf("%-8s %-16s %-6s %14s\n", "TIME", "COMM", "PID", "LAT(us)");
+
+ pb_opts.sample_cb = handle_event;
+ pb_opts.lost_cb = handle_lost_events;
+ pb = perf_buffer__new(bpf_map__fd(obj->maps.events), 64, &pb_opts);
+ err = libbpf_get_error(pb);
+ if (err) {
+ pb = NULL;
+ fprintf(stderr, "failed to open perf buffer: %d\n", err);
+ goto cleanup;
+ }
+
+ while ((err = perf_buffer__poll(pb, 100)) >= 0)
+ ;
+ printf("Error polling perf buffer: %d\n", err);
+
+cleanup:
+ perf_buffer__free(pb);
+ runqslower_bpf__destroy(obj);
+
+ return err != 0;
+}