On 04/29/11 13:23, Ingo Molnar wrote:
>
> * David Ahern <dsahern@xxxxxxxxx> wrote:
>
>>
>>
>> On 04/29/11 08:27, tip-bot for Ingo Molnar wrote:
>>> Commit-ID: 370faf1dd0461ad811852c8abbbcd3d73b1e4fc4
>>> Gitweb: http://git.kernel.org/tip/370faf1dd0461ad811852c8abbbcd3d73b1e4fc4
>>> Author: Ingo Molnar <mingo@xxxxxxx>
>>> AuthorDate: Fri, 29 Apr 2011 16:11:03 +0200
>>> Committer: Ingo Molnar <mingo@xxxxxxx>
>>> CommitDate: Fri, 29 Apr 2011 16:22:33 +0200
>>>
>>> perf stat: Fail softly on unsupported events
>>>
>>> David Ahern reported this perf stat failure:
>>>
>>>> # /tmp/build-perf/perf stat -- sleep 1
>>>> Error: stalled-cycles-frontend event is not supported.
>>>> Fatal: Not all events could be opened.
>>>>
>>>> This is a Dell R410 with an E5620 processor.
>>>
>>> Fail in a softer fashion on unknown/unsupported events.
>>>
>>> Reported-by: David Ahern <dsahern@xxxxxxxxx>
>>> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
>>> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
>>> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
>>> Link: http://lkml.kernel.org/n/tip-7y40wib8n006io7hjpn1dsrm@xxxxxxxxxxxxxx
>>> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
>>> ---
>>> tools/perf/builtin-stat.c | 4 +---
>>> 1 files changed, 1 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
>>> index 9e596ab..c8b535b 100644
>>> --- a/tools/perf/builtin-stat.c
>>> +++ b/tools/perf/builtin-stat.c
>>> @@ -377,7 +377,7 @@ static int run_perf_stat(int argc __used, const char **argv)
>>>
>>> list_for_each_entry(counter, &evsel_list->entries, node) {
>>> if (create_perf_stat_counter(counter) < 0) {
>>> - if (errno == EINVAL || errno == ENOSYS)
>>> + if (errno == EINVAL || errno == ENOSYS || errno == ENOENT)
>>> continue;
>>>
>>> if (errno == EPERM || errno == EACCES) {
>>> @@ -385,8 +385,6 @@ static int run_perf_stat(int argc __used, const char **argv)
>>> "\t Consider tweaking"
>>> " /proc/sys/kernel/perf_event_paranoid or running as root.",
>>> system_wide ? "system-wide " : "");
>>> - } else if (errno == ENOENT) {
>>> - error("%s event is not supported. ", event_name(counter));
>>
>> This silently ignores events -- including ones that a user requested. I
>> think a better option is a continue here.
>>
>> /tmp/build-perf/perf stat -- sleep 1
>> Error: stalled-cycles-frontend event is not supported.
>> Error: stalled-cycles-backend event is not supported.
>
> Ok. Got time to send a patch for that, which prints whichever message you find
> the most intuitive? Perhaps word it as:
>
> Info: stalled-cycles-frontend event is not supported by the kernel
>
> to not yell 'error!' at users all the time?
Yes, Error is the wrong prefix, unless the user asked for the event.
It's also not as simple as a continue; the fd array contains 0 so the
command blocks trying to read from fd 0. e.g.:
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 2492a0e..bb1c4dc 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -318,7 +318,7 @@ static int read_counter(struct perf_evsel *counter)
static int run_perf_stat(int argc __used, const char **argv)
{
unsigned long long t0, t1;
- struct perf_evsel *counter;
+ struct perf_evsel *counter, *n;
int status = 0;
int child_ready_pipe[2], go_pipe[2];
const bool forks = (argc > 0);
@@ -375,7 +375,7 @@ static int run_perf_stat(int argc __used, const char
**argv)
close(child_ready_pipe[0]);
}
- list_for_each_entry(counter, &evsel_list->entries, node) {
+ list_for_each_entry_safe(counter, n, &evsel_list->entries, node) {
if (create_perf_stat_counter(counter) < 0) {
if (errno == EINVAL || errno == ENOSYS)
continue;
@@ -387,6 +387,8 @@ static int run_perf_stat(int argc __used, const char
**argv)
system_wide ? "system-wide " : "");
} else if (errno == ENOENT) {
error("%s event is not supported. ", event_name(counter));
+ list_del(&counter->node);
+ continue;
} else {
error("open_counter returned with %d (%s). "
"/bin/dmesg may provide additional information.\n",
That set the xyarray to -1.
David
>
> Thanks,
>
> Ingo
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