From: Stephane Eranian <eranian@google.com>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
LKML <linux-kernel@vger.kernel.org>,
David Ahern <dsahern@gmail.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Jiri Olsa <jolsa@redhat.com>, Mike Galbraith <efault@gmx.de>,
Namhyung Kim <namhyung@gmail.com>,
Paul Mackerras <paulus@samba.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH V11 09/15] perf: make events stream always parsable
Date: Wed, 21 Aug 2013 15:39:55 +0200 [thread overview]
Message-ID: <CABPqkBRDB6_HvBAYNsZu2=VDhqYuzmYym97T7zWdvAVjuQgQQg@mail.gmail.com> (raw)
In-Reply-To: <520B7F6D.2000004@intel.com>
On Wed, Aug 14, 2013 at 3:00 PM, Adrian Hunter <adrian.hunter@intel.com> wrote:
> On 14/08/13 15:48, Adrian Hunter wrote:
>> The event stream is not always parsable because the format of a sample
>> is dependent on the sample_type of the selected event. When there
>> is more than one selected event and the sample_types are not the
>> same then parsing becomes problematic. A sample can be matched to its
>> selected event using the ID that is allocated when the event is opened.
>> Unfortunately, to get the ID from the sample means first parsing it.
>>
>> This patch adds a new sample format bit PERF_SAMPLE_IDENTIFER that puts
>> the ID at a fixed position so that the ID can be retrieved without
>> parsing the sample. For sample events, that is the first position
>> immediately after the header. For non-sample events, that is the last
>> position.
>>
>> In this respect parsing samples requires that the sample_type and ID
>> values are recorded. For example, perf tools records struct perf_event_attr
>> and the IDs within the perf.data file. Those must be read first
>> before it is possible to parse samples found later in the perf.data file.
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>
> Forgot to add Peter's ack which is here:
>
> http://marc.info/?l=linux-kernel&m=137629757013526&w=2
Tested this patch via libpfm4 and per-event branch-stack.
Works well.
Tested-by: Stephane Eranian <eranian@google.com>
next prev parent reply other threads:[~2013-08-21 13:39 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-14 12:48 [PATCH V11 00/15] perf tools: some fixes and tweaks Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 01/15] perf tools: re-implement debug print function for linking python/perf.so Adrian Hunter
2013-08-29 10:07 ` [tip:perf/core] perf tools: Re-implement " tip-bot for Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 02/15] perf tools: add debug prints Adrian Hunter
2013-08-29 10:07 ` [tip:perf/core] perf tools: Add " tip-bot for Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 03/15] perf tools: allow non-matching sample types Adrian Hunter
2013-08-16 18:41 ` Arnaldo Carvalho de Melo
2013-08-18 19:04 ` Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 04/15] perf tools: add pid to struct thread Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 05/15] perf tools: change machine__findnew_thread() to set thread pid Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 06/15] perf tools: tidy up sample parsing overflow checking Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 07/15] perf tools: remove unnecessary callchain validation Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 08/15] perf tools: remove references to struct ip_event Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 09/15] perf: make events stream always parsable Adrian Hunter
2013-08-14 13:00 ` Adrian Hunter
2013-08-21 13:39 ` Stephane Eranian [this message]
2013-08-14 12:48 ` [PATCH V11 10/15] perf tools: move perf_evlist__config() to a new source file Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 11/15] perf tools: add support for PERF_SAMPLE_IDENTFIER Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 12/15] perf tools: add missing 'abi' member to 'struct regs_dump' Adrian Hunter
2013-08-14 16:36 ` Jiri Olsa
2013-08-14 12:48 ` [PATCH V11 13/15] perf tools: expand perf_event__synthesize_sample() Adrian Hunter
2013-08-14 16:39 ` Jiri Olsa
2013-08-14 12:48 ` [PATCH V11 14/15] perf tools: add a function to calculate sample event size Adrian Hunter
2013-08-14 12:48 ` [PATCH V11 15/15] perf tools: add a sample parsing test Adrian Hunter
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