Re: [PATCH v5 1/6] perf tools: Derive trigger class from auxtrace_snapshot

From: Jiri Olsa
Date: Wed Apr 20 2016 - 03:46:21 EST


On Mon, Apr 18, 2016 at 02:55:27PM +0000, Wang Nan wrote:

SNIP

> -static volatile int auxtrace_snapshot_err;
> static volatile int auxtrace_record__snapshot_started;
> +static DEFINE_TRIGGER(auxtrace_snapshot);
>
> static void sig_handler(int sig)
> {
> @@ -282,11 +247,12 @@ static void record__read_auxtrace_snapshot(struct record *rec)
> {
> pr_debug("Recording AUX area tracing snapshot\n");
> if (record__auxtrace_read_snapshot_all(rec) < 0) {
> - auxtrace_snapshot_err = -1;
> + auxtrace_snapshot_error();
> } else {
> - auxtrace_snapshot_err = auxtrace_record__snapshot_finish(rec->itr);
> - if (!auxtrace_snapshot_err)
> - auxtrace_snapshot_enable();
> + if (auxtrace_record__snapshot_finish(rec->itr))
> + auxtrace_snapshot_error();
> + else
> + auxtrace_snapshot_ready();
> }
> }
>
> @@ -815,21 +781,21 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
> perf_evlist__enable(rec->evlist);
> }
>
> - auxtrace_snapshot_enable();
> + auxtrace_snapshot_ready();
> for (;;) {
> unsigned long long hits = rec->samples;
>
> if (record__mmap_read_all(rec) < 0) {
> - auxtrace_snapshot_disable();
> + auxtrace_snapshot_error();
> err = -1;
> goto out_child;
> }
>
> if (auxtrace_record__snapshot_started) {
> auxtrace_record__snapshot_started = 0;

I'm ok with the chenge, however what I wanted to understand
is why we need auxtrace_record__snapshot_started ;-)

could we get rid of it like in the patch below?

thanks,
jirka


---
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index ad37f6937410..e220bd5eea0e 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -128,7 +128,6 @@ static volatile int done;
static volatile int signr = -1;
static volatile int child_finished;

-static volatile int auxtrace_record__snapshot_started;
static DEFINE_TRIGGER(auxtrace_snapshot);

static void sig_handler(int sig)
@@ -791,8 +790,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
goto out_child;
}

- if (auxtrace_record__snapshot_started) {
- auxtrace_record__snapshot_started = 0;
+ if (auxtrace_snapshot_is_toggled()) {
if (!auxtrace_snapshot_is_error())
record__read_auxtrace_snapshot(rec);
if (auxtrace_snapshot_is_error()) {
@@ -1416,7 +1414,6 @@ static void snapshot_sig_handler(int sig __maybe_unused)
if (!auxtrace_snapshot_is_ready())
return;
auxtrace_snapshot_toggle();
- auxtrace_record__snapshot_started = 1;
if (auxtrace_record__snapshot_start(record.itr))
auxtrace_snapshot_error();
}