From: David Ahern <dsah...@gmail.com>
'perf sched timehist' provides an analysis of scheduling events.
Example usage:
perf sched record -- sleep 1
perf sched timehist
By default it shows the individual schedule events, including the wait
time (time between sched-out and next sched-in events for the task), the
task scheduling delay (time between wakeup and actually running) and run
time for the task:
time cpu task name wait time sch delay run time
[tid/pid] (msec) (msec) (msec)
-------------- ------ -------------------- --------- --------- ---------
79371.874569 [0011] gcc[31949] 0.014 0.000 1.148
79371.874591 [0010] gcc[31951] 0.000 0.000 0.024
79371.874603 [0010] migration/10[59] 3.350 0.004 0.011
79371.874604 [0011] <idle> 1.148 0.000 0.035
79371.874723 [0005] <idle> 0.016 0.000 1.383
79371.874746 [0005] gcc[31949] 0.153 0.078 0.022
...
Times are in msec.usec.
Signed-off-by: David Ahern <dsah...@gmail.com>
Signed-off-by: Namhyung Kim <namhy...@kernel.org>
---
tools/perf/builtin-sched.c | 594 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 589 insertions(+), 5 deletions(-)
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index fb3441211e4b..c0ac0c9557e8 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -13,12 +13,14 @@
#include "util/cloexec.h"
#include "util/thread_map.h"
#include "util/color.h"
+#include "util/stat.h"
#include <subcmd/parse-options.h>
#include "util/trace-event.h"
#include "util/debug.h"
+#include <linux/log2.h>
#include <sys/prctl.h>
#include <sys/resource.h>
@@ -194,6 +196,29 @@ struct perf_sched {
struct perf_sched_map map;
};
+/* per thread run time data */
+struct thread_runtime {
+ u64 last_time; /* time of previous sched in/out event */
+ u64 dt_run; /* run time */
+ u64 dt_wait; /* time between CPU access (off cpu) */
+ u64 dt_delay; /* time between wakeup and sched-in */
+ u64 ready_to_run; /* time of wakeup */
+
+ struct stats run_stats;
+ u64 total_run_time;
+};
+
+/* per event run time data */
+struct evsel_runtime {
+ u64 *last_time; /* time this event was last seen per cpu */
+ u32 ncpu; /* highest cpu slot allocated */
+};
+
+/* track idle times per cpu */
+static struct thread **idle_threads;
+static int idle_max_cpu;
+static char idle_comm[] = "<idle>";
+
static u64 get_nsecs(void)
{
struct timespec ts;
@@ -1654,6 +1679,546 @@ static int perf_sched__read_events(struct perf_sched
*sched)
return rc;
}
+/*
+ * scheduling times are printed as msec.usec
+ */
+static inline void print_sched_time(unsigned long long nsecs, int width)
+{
+ unsigned long msecs;
+ unsigned long usecs;
+
+ msecs = nsecs / NSEC_PER_MSEC;
+ nsecs -= msecs * NSEC_PER_MSEC;
+ usecs = nsecs / NSEC_PER_USEC;
+ printf("%*lu.%03lu ", width, msecs, usecs);
+}
+
+/*
+ * returns runtime data for event, allocating memory for it the
+ * first time it is used.
+ */
+static struct evsel_runtime *perf_evsel__get_runtime(struct perf_evsel *evsel)
+{
+ struct evsel_runtime *r = evsel->priv;
+
+ if (r == NULL) {
+ r = zalloc(sizeof(struct evsel_runtime));
+ evsel->priv = r;
+ }
+
+ return r;
+}
+
+/*
+ * save last time event was seen per cpu
+ */
+static void perf_evsel__save_time(struct perf_evsel *evsel,
+ u64 timestamp, u32 cpu)
+{
+ struct evsel_runtime *r = perf_evsel__get_runtime(evsel);
+
+ if (r == NULL)
+ return;
+
+ if ((cpu >= r->ncpu) || (r->last_time == NULL)) {
+ int i, n = __roundup_pow_of_two(cpu+1);
+ void *p = r->last_time;
+
+ p = realloc(r->last_time, n * sizeof(u64));
+ if (!p)
+ return;
+
+ r->last_time = p;
+ for (i = r->ncpu; i < n; ++i)
+ r->last_time[i] = (u64) 0;
+
+ r->ncpu = n;
+ }
+
+ r->last_time[cpu] = timestamp;
+}
+
+/* returns last time this event was seen on the given cpu */
+static u64 perf_evsel__get_time(struct perf_evsel *evsel, u32 cpu)
+{
+ struct evsel_runtime *r = perf_evsel__get_runtime(evsel);
+
+ if ((r == NULL) || (r->last_time == NULL) || (cpu >= r->ncpu))
+ return 0;
+
+ return r->last_time[cpu];
+}
+
+static int comm_width = 20;
+
+static char *timehist_get_commstr(struct thread *thread)
+{
+ static char str[32];
+ const char *comm = thread__comm_str(thread);
+ pid_t tid = thread->tid;
+ pid_t pid = thread->pid_;
+ int n;
+
+ if (pid == 0)
+ n = scnprintf(str, sizeof(str), "%s", comm);
+
+ else if (tid != pid)
+ n = scnprintf(str, sizeof(str), "%s[%d/%d]", comm, tid, pid);
+
+ else
+ n = scnprintf(str, sizeof(str), "%s[%d]", comm, tid);
+
+ if (n > comm_width)
+ comm_width = n;
+
+ return str;
+}
+
+static void timehist_header(void)
+{
+ printf("%15s %6s ", "time", "cpu");
+
+ printf(" %-20s %9s %9s %9s",
+ "task name", "wait time", "sch delay", "run time");
+
+ printf("\n");
+
+ /*
+ * units row
+ */
+ printf("%15s %-6s ", "", "");
+
+ printf(" %-20s %9s %9s %9s\n", "[tid/pid]", "(msec)", "(msec)",
"(msec)");
+
+ /*
+ * separator
+ */
+ printf("%.15s %.6s ", graph_dotted_line, graph_dotted_line);
+
+ printf(" %.20s %.9s %.9s %.9s",
+ graph_dotted_line, graph_dotted_line, graph_dotted_line,
+ graph_dotted_line);
+
+ printf("\n");
+}
+
+static void timehist_print_sample(struct perf_sample *sample,
+ struct thread *thread)
+{
+ struct thread_runtime *tr = thread__priv(thread);
+ char tstr[64];
+
+ timestamp__scnprintf_usec(sample->time, tstr, sizeof(tstr));
+ printf("%15s [%04d] ", tstr, sample->cpu);
+
+ printf(" %-*s ", comm_width, timehist_get_commstr(thread));
+
+ print_sched_time(tr->dt_wait, 6);
+ print_sched_time(tr->dt_delay, 6);
+ print_sched_time(tr->dt_run, 6);
+ printf("\n");
+}
+
+/*
+ * Explanation of delta-time stats:
+ *
+ * t = time of current schedule out event
+ * tprev = time of previous sched out event
+ * also time of schedule-in event for current task
+ * last_time = time of last sched change event for current task
+ * (i.e, time process was last scheduled out)
+ * ready_to_run = time of wakeup for current task
+ *
+ * -----|------------|------------|------------|------
+ * last ready tprev t
+ * time to run
+ *
+ * |-------- dt_wait --------|
+ * |- dt_delay -|-- dt_run --|
+ *
+ * dt_run = run time of current task
+ * dt_wait = time between last schedule out event for task and tprev
+ * represents time spent off the cpu
+ * dt_delay = time between wakeup and schedule-in of task
+ */
+
+static void timehist_update_runtime_stats(struct thread_runtime *r,
+ u64 t, u64 tprev)
+{
+ r->dt_delay = 0;
+ r->dt_wait = 0;
+ r->dt_run = 0;
+ if (tprev) {
+ r->dt_run = t - tprev;
+ if (r->ready_to_run) {
+ if (r->ready_to_run > tprev)
+ pr_debug("time travel: wakeup time for task >
previous sched_switch event\n");
+ else
+ r->dt_delay = tprev - r->ready_to_run;
+ }
+
+ if (r->last_time > tprev)
+ pr_debug("time travel: last sched out time for task >
previous sched_switch event\n");
+ else if (r->last_time)
+ r->dt_wait = tprev - r->last_time;
+ }
+
+ update_stats(&r->run_stats, r->dt_run);
+ r->total_run_time += r->dt_run;
+}
+
+static bool is_idle_sample(struct perf_sample *sample,
+ struct perf_evsel *evsel)
+{
+ /* pid 0 == swapper == idle task */
+ if (sample->pid == 0)
+ return true;
+
+ if (strcmp(perf_evsel__name(evsel), "sched:sched_switch") == 0) {
+ if (perf_evsel__intval(evsel, sample, "prev_pid") == 0)
+ return true;
+ }
+ return false;
+}
+
+/*
+ * Track idle stats per cpu by maintaining a local thread
+ * struct for the idle task on each cpu.
+ */
+static int init_idle_threads(int ncpu)
+{
+ int i;
+
+ idle_threads = zalloc(ncpu * sizeof(struct thread *));
+ if (!idle_threads)
+ return -ENOMEM;
+
+ idle_max_cpu = ncpu - 1;
+
+ /* allocate the actual thread struct if needed */
+ for (i = 0; i < ncpu; ++i) {
+ idle_threads[i] = thread__new(0, 0);
+ if (idle_threads[i] == NULL)
+ return -ENOMEM;
+
+ thread__set_comm(idle_threads[i], idle_comm, 0);
+ }
+
+ return 0;
+}
+
+static void free_idle_threads(void)
+{
+ int i;
+
+ if (idle_threads == NULL)
+ return;
+
+ for (i = 0; i <= idle_max_cpu; ++i) {
+ if ((idle_threads[i]))
+ thread__delete(idle_threads[i]);
+ }
+
+ free(idle_threads);
+}
+
+static struct thread *get_idle_thread(int cpu)
+{
+ /*
+ * expand/allocate array of pointers to local thread
+ * structs if needed
+ */
+ if ((cpu >= idle_max_cpu) || (idle_threads == NULL)) {
+ int i, j = __roundup_pow_of_two(cpu+1);
+ void *p;
+
+ p = realloc(idle_threads, j * sizeof(struct thread *));
+ if (!p)
+ return NULL;
+
+ idle_threads = (struct thread **) p;
+ i = idle_max_cpu ? idle_max_cpu + 1 : 0;
+ for (; i < j; ++i)
+ idle_threads[i] = NULL;
+
+ idle_max_cpu = j;
+ }
+
+ /* allocate a new thread struct if needed */
+ if (idle_threads[cpu] == NULL) {
+ idle_threads[cpu] = thread__new(0, 0);
+
+ if (idle_threads[cpu]) {
+ idle_threads[cpu]->tid = 0;
+ thread__set_comm(idle_threads[cpu], idle_comm, 0);
+ }
+ }
+
+ return idle_threads[cpu];
+}
+
+/*
+ * handle runtime stats saved per thread
+ */
+static struct thread_runtime *thread__init_runtime(struct thread *thread)
+{
+ struct thread_runtime *r;
+
+ r = zalloc(sizeof(struct thread_runtime));
+ if (!r)
+ return NULL;
+
+ init_stats(&r->run_stats);
+ thread__set_priv(thread, r);
+
+ return r;
+}
+
+static struct thread_runtime *thread__get_runtime(struct thread *thread)
+{
+ struct thread_runtime *tr;
+
+ tr = thread__priv(thread);
+ if (tr == NULL) {
+ tr = thread__init_runtime(thread);
+ if (tr == NULL)
+ pr_debug("Failed to malloc memory for runtime data.\n");
+ }
+
+ return tr;
+}
+
+static struct thread *timehist_get_thread(struct perf_sample *sample,
+ struct machine *machine,
+ struct perf_evsel *evsel)
+{
+ struct thread *thread;
+
+ if (is_idle_sample(sample, evsel)) {
+ thread = get_idle_thread(sample->cpu);
+ if (thread == NULL)
+ pr_err("Failed to get idle thread for cpu %d.\n",
sample->cpu);
+
+ } else {
+ thread = machine__findnew_thread(machine, sample->pid,
sample->tid);
+ if (thread == NULL) {
+ pr_debug("Failed to get thread for tid %d. skipping
sample.\n",
+ sample->tid);
+ }
+ }
+
+ return thread;
+}
+
+static bool timehist_skip_sample(struct thread *thread)
+{
+ bool rc = false;
+
+ if (thread__is_filtered(thread))
+ rc = true;
+
+ return rc;
+}
+
+static int timehist_sched_wakeup_event(struct perf_tool *tool __maybe_unused,
+ union perf_event *event __maybe_unused,
+ struct perf_evsel *evsel,
+ struct perf_sample *sample,
+ struct machine *machine)
+{
+ struct thread *thread;
+ struct thread_runtime *tr = NULL;
+ /* want pid of awakened task not pid in sample */
+ const u32 pid = perf_evsel__intval(evsel, sample, "pid");
+
+ thread = machine__findnew_thread(machine, 0, pid);
+ if (thread == NULL)
+ return -1;
+
+ tr = thread__get_runtime(thread);
+ if (tr == NULL)
+ return -1;
+
+ if (tr->ready_to_run == 0)
+ tr->ready_to_run = sample->time;
+
+ return 0;
+}
+
+static int timehist_sched_change_event(struct perf_tool *tool __maybe_unused,
+ union perf_event *event,
+ struct perf_evsel *evsel,
+ struct perf_sample *sample,
+ struct machine *machine)
+{
+ struct addr_location al;
+ struct thread *thread;
+ struct thread_runtime *tr = NULL;
+ u64 tprev;
+ int rc = 0;
+
+ if (machine__resolve(machine, &al, sample) < 0) {
+ pr_err("problem processing %d event. skipping it\n",
+ event->header.type);
+ rc = -1;
+ goto out;
+ }
+
+ thread = timehist_get_thread(sample, machine, evsel);
+ if (thread == NULL) {
+ rc = -1;
+ goto out;
+ }
+
+ if (timehist_skip_sample(thread))
+ goto out;
+
+ tr = thread__get_runtime(thread);
+ if (tr == NULL) {
+ rc = -1;
+ goto out;
+ }
+
+ tprev = perf_evsel__get_time(evsel, sample->cpu);
+
+ timehist_update_runtime_stats(tr, sample->time, tprev);
+ timehist_print_sample(sample, thread);
+
+out:
+ if (tr) {
+ /* time of this sched_switch event becomes last time task seen
*/
+ tr->last_time = sample->time;
+
+ /* sched out event for task so reset ready to run time */
+ tr->ready_to_run = 0;
+ }
+
+ perf_evsel__save_time(evsel, sample->time, sample->cpu);
+
+ return rc;
+}
+
+static int timehist_sched_switch_event(struct perf_tool *tool,
+ union perf_event *event,
+ struct perf_evsel *evsel,
+ struct perf_sample *sample,
+ struct machine *machine __maybe_unused)
+{
+ return timehist_sched_change_event(tool, event, evsel, sample, machine);
+}
+
+static int process_lost(struct perf_tool *tool __maybe_unused,
+ union perf_event *event,
+ struct perf_sample *sample,
+ struct machine *machine __maybe_unused)
+{
+ char tstr[64];
+
+ timestamp__scnprintf_usec(sample->time, tstr, sizeof(tstr));
+ printf("%15s ", tstr);
+ printf("lost %" PRIu64 " events on cpu %d\n", event->lost.lost,
sample->cpu);
+
+ return 0;
+}
+
+
+typedef int (*sched_handler)(struct perf_tool *tool,
+ union perf_event *event,
+ struct perf_evsel *evsel,
+ struct perf_sample *sample,
+ struct machine *machine);
+
+static int perf_timehist__process_sample(struct perf_tool *tool,
+ union perf_event *event,
+ struct perf_sample *sample,
+ struct perf_evsel *evsel,
+ struct machine *machine)
+{
+ struct perf_sched *sched = container_of(tool, struct perf_sched, tool);
+ int err = 0;
+ int this_cpu = sample->cpu;
+
+ if (this_cpu > sched->max_cpu)
+ sched->max_cpu = this_cpu;
+
+ if (evsel->handler != NULL) {
+ sched_handler f = evsel->handler;
+
+ err = f(tool, event, evsel, sample, machine);
+ }
+
+ return err;
+}
+
+static int perf_sched__timehist(struct perf_sched *sched)
+{
+ const struct perf_evsel_str_handler handlers[] = {
+ { "sched:sched_switch", timehist_sched_switch_event, },
+ { "sched:sched_wakeup", timehist_sched_wakeup_event, },
+ { "sched:sched_wakeup_new", timehist_sched_wakeup_event, },
+ };
+ struct perf_data_file file = {
+ .path = input_name,
+ .mode = PERF_DATA_MODE_READ,
+ };
+
+ struct perf_session *session;
+ int err = -1;
+
+ /*
+ * event handlers for timehist option
+ */
+ sched->tool.sample = perf_timehist__process_sample;
+ sched->tool.mmap = perf_event__process_mmap;
+ sched->tool.comm = perf_event__process_comm;
+ sched->tool.exit = perf_event__process_exit;
+ sched->tool.fork = perf_event__process_fork;
+ sched->tool.lost = process_lost;
+ sched->tool.attr = perf_event__process_attr;
+ sched->tool.tracing_data = perf_event__process_tracing_data;
+ sched->tool.build_id = perf_event__process_build_id;
+
+ sched->tool.ordered_events = true;
+ sched->tool.ordering_requires_timestamps = true;
+
+ session = perf_session__new(&file, false, &sched->tool);
+ if (session == NULL)
+ return -ENOMEM;
+
+ symbol__init(&session->header.env);
+
+ setup_pager();
+
+ /* setup per-evsel handlers */
+ if (perf_session__set_tracepoints_handlers(session, handlers))
+ goto out;
+
+ if (!perf_session__has_traces(session, "record -R"))
+ goto out;
+
+ /* pre-allocate struct for per-CPU idle stats */
+ sched->max_cpu = session->header.env.nr_cpus_online;
+ if (sched->max_cpu == 0)
+ sched->max_cpu = 4;
+ if (init_idle_threads(sched->max_cpu))
+ goto out;
+
+ timehist_header();
+
+ err = perf_session__process_events(session);
+ if (err) {
+ pr_err("Failed to process events, error %d", err);
+ goto out;
+ }
+
+out:
+ free_idle_threads();
+ perf_session__delete(session);
+
+ return err;
+}
+
+
static void print_bad_events(struct perf_sched *sched)
{
if (sched->nr_unordered_timestamps && sched->nr_timestamps) {
@@ -1970,8 +2535,6 @@ int cmd_sched(int argc, const char **argv, const char
*prefix __maybe_unused)
const struct option latency_options[] = {
OPT_STRING('s', "sort", &sched.sort_order, "key[,key2...]",
"sort by key(s): runtime, switch, avg, max"),
- OPT_INCR('v', "verbose", &verbose,
- "be more verbose (show symbol address, etc)"),
OPT_INTEGER('C', "CPU", &sched.profile_cpu,
"CPU to profile on"),
OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
@@ -1983,8 +2546,6 @@ int cmd_sched(int argc, const char **argv, const char
*prefix __maybe_unused)
const struct option replay_options[] = {
OPT_UINTEGER('r', "repeat", &sched.replay_repeat,
"repeat the workload replay N times (-1: infinite)"),
- OPT_INCR('v', "verbose", &verbose,
- "be more verbose (show symbol address, etc)"),
OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
"dump raw trace in ASCII"),
OPT_BOOLEAN('f', "force", &sched.force, "don't complain, do it"),
@@ -2001,6 +2562,16 @@ int cmd_sched(int argc, const char **argv, const char
*prefix __maybe_unused)
"display given CPUs in map"),
OPT_PARENT(sched_options)
};
+ const struct option timehist_options[] = {
+ OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
+ "file", "vmlinux pathname"),
+ OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
+ "file", "kallsyms pathname"),
+ OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
+ "Look for files with symbols relative to this directory"),
+ OPT_PARENT(sched_options)
+ };
+
const char * const latency_usage[] = {
"perf sched latency [<options>]",
NULL
@@ -2013,8 +2584,13 @@ int cmd_sched(int argc, const char **argv, const char
*prefix __maybe_unused)
"perf sched map [<options>]",
NULL
};
+ const char * const timehist_usage[] = {
+ "perf sched timehist [<options>]",
+ NULL
+ };
const char *const sched_subcommands[] = { "record", "latency", "map",
- "replay", "script", NULL };
+ "replay", "script",
+ "timehist", NULL };
const char *sched_usage[] = {
NULL,
NULL
@@ -2077,6 +2653,14 @@ int cmd_sched(int argc, const char **argv, const char
*prefix __maybe_unused)
usage_with_options(replay_usage,
replay_options);
}
return perf_sched__replay(&sched);
+ } else if (!strcmp(argv[0], "timehist")) {
+ if (argc) {
+ argc = parse_options(argc, argv, timehist_options,
+ timehist_usage, 0);
+ if (argc)
+ usage_with_options(timehist_usage,
timehist_options);
+ }
+ return perf_sched__timehist(&sched);
} else {
usage_with_options(sched_usage, sched_options);
}
--
2.10.1
