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Subject[PATCH 5/5] perf: teach perf inject to merge sched_switch* events for profiling sleep times
Date
The time difference between sched_switch and sched_switch_finish is a time
when a task wasn't being executed on a cpu.

My code saves the time of sched_switch event for each process and
when it meets stat_switch_finish, it sets time difference in sample->period
and saves this new sample in the new perf.data.

As a result we can see where and how long task sleeps.

Signed-off-by: Andrew Vagin <avagin@openvz.org>
---
tools/perf/builtin-inject.c | 88 ++++++++++++++++++++++++++++++++++++++++--
1 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index bc30a40..631051e 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -13,6 +13,8 @@
#include "util/debug.h"

#include "util/parse-options.h"
+#include "util/trace-event.h"
+

static char const *input_name = "-";
static const char *output_name = "-";
@@ -21,6 +23,9 @@ static int output;
static u64 bytes_written = 0;

static bool inject_build_ids;
+static bool inject_sched_stat;
+
+struct perf_session *session;

static int perf_event__repipe_synth(struct perf_tool *tool __used,
union perf_event *event,
@@ -47,7 +52,7 @@ static int perf_event__repipe_synth(struct perf_tool *tool __used,

static int perf_event__repipe_op2_synth(struct perf_tool *tool,
union perf_event *event,
- struct perf_session *session __used)
+ struct perf_session *s __used)
{
return perf_event__repipe_synth(tool, event, NULL);
}
@@ -59,7 +64,7 @@ static int perf_event__repipe_event_type_synth(struct perf_tool *tool,
}

static int perf_event__repipe_tracing_data_synth(union perf_event *event,
- struct perf_session *session __used)
+ struct perf_session *s __used)
{
return perf_event__repipe_synth(NULL, event, NULL);
}
@@ -119,12 +124,12 @@ static int perf_event__repipe_task(struct perf_tool *tool,
}

static int perf_event__repipe_tracing_data(union perf_event *event,
- struct perf_session *session)
+ struct perf_session *s)
{
int err;

perf_event__repipe_synth(NULL, event, NULL);
- err = perf_event__process_tracing_data(event, session);
+ err = perf_event__process_tracing_data(event, s);

return err;
}
@@ -210,6 +215,75 @@ repipe:
return 0;
}

+struct event_entry
+{
+ struct list_head list;
+ u32 pid;
+ u64 time;
+};
+
+static LIST_HEAD(samples);
+
+static int perf_event__sched_stat(struct perf_tool *tool,
+ union perf_event *event,
+ struct perf_sample *sample,
+ struct perf_evsel *evsel __used,
+ struct machine *machine)
+{
+ int type;
+ struct event_format *e;
+ const char *evname = NULL;
+ struct event_entry *ent;
+
+ type = trace_parse_common_type(sample->raw_data);
+ e = trace_find_event(type);
+ if (e)
+ evname = e->name;
+
+ if (!strcmp(evname, "sched_switch")) {
+ list_for_each_entry(ent, &samples, list)
+ if (sample->pid == ent->pid)
+ break;
+
+ if (&ent->list != &samples) {
+ list_del(&ent->list);
+ free(ent);
+ }
+
+ ent = malloc(sizeof(struct event_entry));
+ ent->pid = sample->pid;
+ ent->time = sample->time;
+ list_add(&ent->list, &samples);
+ return 0;
+
+ } else if (!strcmp(evname, "sched_switch_finish")) {
+ union perf_event *event_sw;
+
+ list_for_each_entry(ent, &samples, list)
+ if (sample->pid == ent->pid)
+ break;
+
+ if (&ent->list == &samples) {
+ pr_debug("Could not find sched_switch for pid %u\n", sample->pid);
+ return 0;
+ }
+
+ event_sw = malloc(event->header.size);
+ if (event_sw == NULL)
+ return -1;
+
+ memcpy(event_sw, event, event->header.size);
+ sample->period = sample->time - ent->time;
+ perf_session__synthesize_sample(session, event_sw, sample);
+ perf_event__repipe(tool, event_sw, sample, machine);
+ free(event_sw);
+ return 0;
+ }
+
+ perf_event__repipe(tool, event, sample, machine);
+
+ return 0;
+}
struct perf_tool perf_inject = {
.sample = perf_event__repipe_sample,
.mmap = perf_event__repipe,
@@ -235,7 +309,6 @@ static void sig_handler(int sig __attribute__((__unused__)))

static int __cmd_inject(void)
{
- struct perf_session *session;
int ret = -EINVAL;

signal(SIGINT, sig_handler);
@@ -245,6 +318,9 @@ static int __cmd_inject(void)
perf_inject.mmap = perf_event__repipe_mmap;
perf_inject.fork = perf_event__repipe_task;
perf_inject.tracing_data = perf_event__repipe_tracing_data;
+ } else if (inject_sched_stat) {
+ perf_inject.sample = perf_event__sched_stat;
+ perf_inject.ordered_samples = true;
}

session = perf_session__new(input_name, O_RDONLY, false, true, &perf_inject);
@@ -272,6 +348,8 @@ static const char * const report_usage[] = {
static const struct option options[] = {
OPT_BOOLEAN('b', "build-ids", &inject_build_ids,
"Inject build-ids into the output stream"),
+ OPT_BOOLEAN('s', "sched-switch", &inject_sched_stat,
+ "merge sched-switch* for profiling sleep time"),
OPT_STRING('i', "input", &input_name, "file",
"input file name"),
OPT_STRING('o', "output", &output_name, "file",
--
1.7.1


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