Re: [drm/i915/gt] 8c3b1ba0e7: perf-sanity-tests.Parse_event_definition_strings.fail
From: Jiri Olsa
Date: Thu Feb 25 2021 - 14:05:16 EST
On Thu, Feb 25, 2021 at 07:50:46PM +0100, Jiri Olsa wrote:
>
On Thu, Feb 25, 2021 at 07:16:44PM +0100, Jiri Olsa wrote:
>
> On Thu, Feb 25, 2021 at 02:33:57PM +0100, Jiri Olsa wrote:
>
> > On Thu, Feb 25, 2021 at 04:06:23PM +0800, Jin, Yao wrote:
>
> > > Hi Chris, Arnaldo, Jiri,
>
> > >
>
> > > We observe the parsing error for "software/xxx/" on some platforms.
>
> > >
>
> > > For example,
>
> > >
>
> > > # perf stat -e software/r1a/ -a -- sleep 1
>
> > > event syntax error: 'software/r1a/'
>
> > > \___ parser error
>
> > > Run 'perf list' for a list of valid events
>
> > >
>
> > > Usage: perf stat [<options>] [<command>]
>
> > >
>
> > > -e, --event <event> event selector. use 'perf list' to list available events
>
> > >
>
> > > And perf test is failed too.
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> > >
>
> > > # perf test 6 -vv
>
> > > ...
>
> > > running test 4 'software/r1a/'failed to parse event 'software/r1a/', err 1, str 'parser error'
>
> > > event syntax error: 'software/r1a/'
>
> > > \___ parser error
>
> > >
>
> > > running test 4 'software/r0x1a/'failed to parse event 'software/r0x1a/', err 1, str 'parser error'
>
> > > event syntax error: 'software/r0x1a/'
>
> > > \___ parser error
>
> > > ...
>
> > >
>
> > > The issue should be the conflict between event "i915/software-gt-awake-time/" and pmu "software".
>
> > >
>
> > > # perf list | grep i915/software
>
> > > i915/software-gt-awake-time/ [Kernel PMU event]
>
> > >
>
> > > Perf supports the event format as "prefix-xxx-suffix", so the "software"
>
> > > string in "software-gt-awake-time" is added to perf_pmu_events_list as
>
> > > PMU_EVENT_SYMBOL_PREFIX. When parsing the string such as "software/xxx/",
>
> > > it’s parsed as PMU_EVENT_SYMBOL_PREFIX for "software", then it would error
>
> > > out in next processing.
>
> > >
>
> > > So the easy way is to rename "software-gt-awake-time" to "gt-awake-time",
>
> > > right? Otherwise we have to hardcode something in perf tool.
>
> > >
>
> > > What do you think of this issue and the solution?
>
> > >
>
> > > BTW, as the robot reported, it's related to the commit 8c3b1ba0e7ea
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> > > ("drm/i915/gt: Track the overall awake/busy time").
>
> >
>
> > yes, I think you're right.. I'll try to reproduce and check on this
>
> >
>
> > I'm still not clear why is that parsing fail if those 2 events are
>
> > distinguished by - and / ... but yep, we are asking for trouble in
>
> > here ;-)
>
> >
>
> > I think we could either prioritaze one or add extra check when we
>
> > add prefix-xxx-suffix events and do not add ones that have conflict..
>
> > that seems like best solution to me now
>
>
>
> would patch below work for you?
>
>
>
> jirka
>
>
and now with more fixes after I ran tests ;-)
>
>
we should perhaps add also same check for non '-' aliases, I'll check
and one more version ;-)
jirka
---
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 42c84adeb2fb..d9e795056d15 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -2028,30 +2028,49 @@ static void perf_pmu__parse_init(void)
perf_pmu_events_list_num = -1;
return;
}
- perf_pmu_events_list = malloc(sizeof(struct perf_pmu_event_symbol) * len);
+ perf_pmu_events_list = zalloc(sizeof(struct perf_pmu_event_symbol) * len);
if (!perf_pmu_events_list)
return;
- perf_pmu_events_list_num = len;
len = 0;
pmu = NULL;
while ((pmu = perf_pmu__scan(pmu)) != NULL) {
list_for_each_entry(alias, &pmu->aliases, list) {
struct perf_pmu_event_symbol *p = perf_pmu_events_list + len;
- char *tmp = strchr(alias->name, '-');
+ char *prefix = strdup(alias->name);
+ char *tmp = strchr(prefix, '-');
+
+ if (tmp != NULL)
+ *tmp = 0;
+
+ /*
+ * Skip any prefix that conflicts with pmu name,
+ * otherwise the event parser gets confused.
+ */
+ if (perf_pmu__find(prefix)) {
+ pr_debug2("perf_pmu__parse_init: skipping conflicting alias '%s'\n",
+ alias->name);
+ free(prefix);
+ continue;
+ }
if (tmp != NULL) {
- SET_SYMBOL(strndup(alias->name, tmp - alias->name),
- PMU_EVENT_SYMBOL_PREFIX);
+ SET_SYMBOL(prefix, PMU_EVENT_SYMBOL_PREFIX);
p++;
SET_SYMBOL(strdup(++tmp), PMU_EVENT_SYMBOL_SUFFIX);
len += 2;
} else {
- SET_SYMBOL(strdup(alias->name), PMU_EVENT_SYMBOL);
+ SET_SYMBOL(prefix, PMU_EVENT_SYMBOL);
len++;
}
}
}
+
+ /* unlikely, but still.. */
+ if (!len)
+ goto err;
+ perf_pmu_events_list_num = len;
+
qsort(perf_pmu_events_list, len,
sizeof(struct perf_pmu_event_symbol), comp_pmu);