linux-kernel - Re: [PULL 1/2] perf/tool: Fix usage of trace events with '-' in trace system name.

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Message-ID: <534E8623.3000608@de.ibm.com>
Date:	Wed, 16 Apr 2014 15:31:15 +0200
From:	Christian Borntraeger <borntraeger@...ibm.com>
To:	Jiri Olsa <jolsa@...hat.com>
CC:	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	linux-kernel@...r.kernel.org, KVM <kvm@...r.kernel.org>,
	Alexander Yarygin <yarygin@...ux.vnet.ibm.com>
Subject: Re: [PULL 1/2] perf/tool: Fix usage of trace events with '-' in trace
 system name.

On 16/04/14 15:28, Christian Borntraeger wrote:
> On 16/04/14 15:00, Jiri Olsa wrote:
>> On Wed, Apr 09, 2014 at 04:21:58PM +0200, Christian Borntraeger wrote:
>>> From: Alexander Yarygin <yarygin@...ux.vnet.ibm.com>
>>>
>>> Trace events potentially can have a '-' in their trace system name,
>>> e.g. kvm on s390 defines kvm-s390:* tracepoints.
>>> tools/perf could not parse them, because there was no rule for this:
>>> $ sudo ./perf top -e "kvm-s390:*"
>>> invalid or unsupported event: 'kvm-s390:*'
>>>
>>> This patch allows '-' to be a part of PE_NAME token, so tracepoints
>>> with '-' can be parsed by the event_legacy_tracepoint rule.
>>> Without the patch, perf will not accept such tracepoints in the -e
>>> option.
>>>
>>> Signed-off-by: Alexander Yarygin <yarygin@...ux.vnet.ibm.com>
>>> Signed-off-by: Christian Borntraeger <borntraeger@...ibm.com>
>>> ---
>>>  tools/perf/util/parse-events.l |    2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
>>> index 3432995..ca20da7 100644
>>> --- a/tools/perf/util/parse-events.l
>>> +++ b/tools/perf/util/parse-events.l
>>> @@ -199,7 +199,7 @@ r{num_raw_hex}		{ return raw(yyscanner); }
>>>  {num_hex}		{ return value(yyscanner, 16); }
>>>  
>>>  {modifier_event}	{ return str(yyscanner, PE_MODIFIER_EVENT); }
>>> -{name}			{ return str(yyscanner, PE_NAME); }
>>> +{name_minus}			{ return str(yyscanner, PE_NAME); }
>>>  "/"			{ BEGIN(config); return '/'; }
>>>  -			{ return '-'; }
>>>  ,			{ BEGIN(event); return ','; }
>>
>> this breaks parsing of cache events like:
>>
>>   $ perf record -e 'L1-dcache-loads' ls
>>
>> also test 10 (same issue):
>>   $ ./perf test 10
>>   10: roundtrip evsel->name check                            : FAILED!
>>
>>
>> it might be little tricky to fix, let me know if you
>> have any troubles with that, I could look on it
> 
> Hmm, so do you prefer tackling this problem directly at  event_legacy_tracepoint, e.g.
> like in
> https://lkml.org/lkml/2014/3/24/364

A totally different approach would be to rename the kvm-s390 trace events to kvm_s390.


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