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From: Frederic Weisbecker <fweisbec@gmail.com>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: perf: store and retrieve trace event names in the perf.data file
Date: Mon, 10 Aug 2009 01:04:31 +0200	[thread overview]
Message-ID: <20090809230430.GB6089@nowhere> (raw)
In-Reply-To: <4A7F554A.8080402@linux.intel.com>

On Sun, Aug 09, 2009 at 04:01:30PM -0700, Arjan van de Ven wrote:
> Frederic Weisbecker wrote:
>> On Sun, Aug 09, 2009 at 02:49:23PM -0700, Arjan van de Ven wrote:
>>> In order to be able to use trace events, a key aspect is the "type" field;
>>> this is the id of the event that you recorded, as stored in the /sys/kernel/debug/events/*/*/id file.
>>> What is currently missing is a way to map the id number (which is not abi stable)
>>> to the event that was recorded.
>>
>>
>>
>> We already have that.
>> See tools/perf/util/parse-events.c: char *tracepoint_id_to_name(u64 id)
>
>
> sadly... we don't.
>
> You do it *on the same boot and machine* as you created the perf.data file.
> You don't have it when you reboot into a new kernel, or move the perf.data file
> to a new machine........
>
> Which is to be honest a very common usecase.


Ah right... I always forget the offline report case.
But you can at least reuse this existing helper to resolve
the id to name.


  reply	other threads:[~2009-08-09 23:04 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-09 21:49 perf: store and retrieve trace event names in the perf.data file Arjan van de Ven
2009-08-09 22:44 ` Frederic Weisbecker
2009-08-09 23:01   ` Arjan van de Ven
2009-08-09 23:04     ` Frederic Weisbecker [this message]
2009-08-09 23:10       ` Arjan van de Ven
2009-08-10  9:50 ` Peter Zijlstra

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