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Date: Wed, 11 Dec 2013 14:37:11 +0200
From: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To: Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Cc: Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
David Ahern <dsahern@...il.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Jiri Olsa <jolsa@...hat.com>, Mike Galbraith <efault@....de>,
Namhyung Kim <namhyung@...il.com>,
Paul Mackerras <paulus@...ba.org>,
Stephane Eranian <eranian@...gle.com>,
Andi Kleen <ak@...ux.intel.com>,
Adrian Hunter <adrian.hunter@...el.com>
Subject: [PATCH v0 59/71] perf record: Add Instruction Tracing Snapshot Mode support
From: Adrian Hunter <adrian.hunter@...el.com>
Add a new option and support for Instruction
Tracing Snapshot Mode. When the new option is
selected, no Instruction Tracing data is
captured until a signal (SIGUSR2) is received.
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
tools/perf/Documentation/perf-record.txt | 7 +++
tools/perf/builtin-record.c | 90 +++++++++++++++++++++++++++++++-
2 files changed, 95 insertions(+), 2 deletions(-)
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 58bd3c1..279c808 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -216,6 +216,13 @@ if combined with -a or -C options.
Enable Instruction Trace sampling. Each sample captures the specified number of
bytes (default 4096) of trace. Instruction Tracing config can also be specified.
+-S::
+--snapshot::
+Select Instruction Tracing Snapshot Mode. This option is valid only with an
+Instruction Tracing event. Optionally the number of bytes to capture per
+snapshot can be specified. In Snapshot Mode, trace data is captured only when
+signal SIGUSR2 is received.
+
SEE ALSO
--------
linkperf:perf-stat[1], linkperf:perf-list[1]
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index e75a15e..46c451c 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -188,9 +188,29 @@ static int perf_record__itrace_mmap_read(struct perf_record *rec,
return 0;
}
+static int perf_record__itrace_mmap_read_snapshot(struct perf_record *rec,
+ struct itrace_mmap *mm)
+{
+ int ret;
+
+ ret = itrace_mmap__read_snapshot(mm, rec->itr, &rec->tool,
+ perf_record__process_itrace,
+ rec->opts.itrace_snapshot_size);
+ if (ret < 0)
+ return ret;
+
+ if (ret)
+ rec->samples++;
+
+ return 0;
+}
+
static volatile int done = 0;
static volatile int signr = -1;
static volatile int child_finished = 0;
+static volatile int itrace_snapshot_enabled;
+static volatile int itrace_snapshot_err;
+static volatile int itrace_record__snapshot_started;
static void sig_handler(int sig)
{
@@ -258,7 +278,7 @@ try_again:
if (perf_evlist__mmap_ex(evlist, opts->mmap_pages, false,
opts->itrace_mmap_pages,
- false) < 0) {
+ opts->itrace_snapshot_mode) < 0) {
if (errno == EPERM) {
pr_err("Permission error mapping pages.\n"
"Consider increasing "
@@ -368,7 +388,7 @@ static int perf_record__mmap_read_all(struct perf_record *rec)
}
}
- if (mm->base &&
+ if (mm->base && !rec->opts.itrace_snapshot_mode &&
perf_record__itrace_mmap_read(rec, mm) != 0) {
rc = -1;
goto out;
@@ -405,6 +425,41 @@ static void perf_record__init_features(struct perf_record *rec)
perf_header__clear_feat(&session->header, HEADER_ITRACE);
}
+static int perf_record__itrace_read_snapshot_all(struct perf_record *rec)
+{
+ int i;
+ int rc = 0;
+
+ for (i = 0; i < rec->evlist->nr_mmaps; i++) {
+ struct itrace_mmap *mm =
+ &rec->evlist->mmap[i].itrace_mmap;
+
+ if (!mm->base)
+ continue;
+
+ if (perf_record__itrace_mmap_read_snapshot(rec, mm) != 0) {
+ rc = -1;
+ goto out;
+ }
+ }
+out:
+ return rc;
+}
+
+static void perf_record__read_itrace_snapshot(struct perf_record *rec)
+{
+ pr_debug("Recording instruction tracing snapshot\n");
+ if (perf_record__itrace_read_snapshot_all(rec) < 0) {
+ itrace_snapshot_err = -1;
+ } else {
+ itrace_snapshot_err = itrace_record__snapshot_finish(rec->itr);
+ if (!itrace_snapshot_err)
+ itrace_snapshot_enabled = 1;
+ }
+}
+
+static void snapshot_sig_handler(int sig);
+
static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
{
int err;
@@ -425,6 +480,10 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
signal(SIGINT, sig_handler);
signal(SIGUSR1, sig_handler);
signal(SIGTERM, sig_handler);
+ if (rec->opts.itrace_snapshot_mode)
+ signal(SIGUSR2, snapshot_sig_handler);
+ else
+ signal(SIGUSR2, SIG_IGN);
session = perf_session__new(file, false, NULL);
if (session == NULL) {
@@ -574,14 +633,27 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
if (forks)
perf_evlist__start_workload(evsel_list);
+ itrace_snapshot_enabled = 1;
for (;;) {
int hits = rec->samples;
if (perf_record__mmap_read_all(rec) < 0) {
+ itrace_snapshot_enabled = 0;
err = -1;
goto out_delete_session;
}
+ if (itrace_record__snapshot_started) {
+ itrace_record__snapshot_started = 0;
+ if (!itrace_snapshot_err)
+ perf_record__read_itrace_snapshot(rec);
+ if (itrace_snapshot_err) {
+ pr_err("Instruction tracing snapshot failed\n");
+ err = -1;
+ goto out_delete_session;
+ }
+ }
+
if (hits == rec->samples) {
if (done)
break;
@@ -595,10 +667,12 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
* disable events in this case.
*/
if (done && !disabled && !target__none(&opts->target)) {
+ itrace_snapshot_enabled = 0;
perf_evlist__disable(evsel_list);
disabled = true;
}
}
+ itrace_snapshot_enabled = 0;
if (quiet || signr == SIGUSR1)
return 0;
@@ -998,6 +1072,9 @@ const struct option record_options[] = {
OPT_CALLBACK_OPTARG('I', "itrace", &record.opts, &record.itr, "opts",
"sample Instruction Trace",
itrace_parse_sample_options),
+ OPT_CALLBACK_OPTARG('S', "snapshot", &record.opts, &record.itr, "opts",
+ "Instruction Tracing Snapshot Mode",
+ itrace_parse_snapshot_options),
OPT_END()
};
@@ -1096,3 +1173,12 @@ out_itrace_free:
itrace_record__free(rec->itr);
return err;
}
+
+static void snapshot_sig_handler(int sig __maybe_unused)
+{
+ if (!itrace_snapshot_enabled)
+ return;
+ itrace_snapshot_enabled = 0;
+ itrace_snapshot_err = itrace_record__snapshot_start(record.itr);
+ itrace_record__snapshot_started = 1;
+}
--
1.8.5.1
--
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