From: Robert Richter <robert.richter@amd.com>
To: Stephane Eranian <eranian@google.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"acme@redhat.com" <acme@redhat.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"dsahern@gmail.com" <dsahern@gmail.com>,
"ak@linux.intel.com" <ak@linux.intel.com>,
"mingo@elte.hu" <mingo@elte.hu>
Subject: Re: [PATCH] perf: make perf.data more self-descriptive (v8)
Date: Wed, 30 Nov 2011 16:08:29 +0100 [thread overview]
Message-ID: <20111130150829.GA15738@erda.amd.com> (raw)
In-Reply-To: <CABPqkBTR3tEGh7LymuS_JJR5SuCZfjTxZP-6qNxmZtBf0Zt9bg@mail.gmail.com>
On 29.11.11 10:35:24, Stephane Eranian wrote:
> sec_start = header->data_offset + header->data_size;
> lseek(fd, sec_start + sec_size, SEEK_SET);
>
> err = do_write_feat(fd, header, HEADER_TRACE_INFO, &p, evlist);
> if (err)
> goto out_free;
>
> err = do_write_feat(fd, header, HEADER_BUILD_ID, &p, evlist);
> if (err) {
> perf_header__clear_feat(header, HEADER_BUILD_ID);
> goto out_free;
> }
>
> The 'clear_feat' is missing for TRACE_INFO, that's all. The question is:
> is case do_write_feat(trace_info) fails, is there still a way to parse the file
> correctly? If not, then perf should bail out, if yes, then we need to add the
> clear_feat(TRACE_INFO) in case of error.
The question is, if do_write_feat() fails for HEADER_TRACE_INFO or
HEADER_BUILD_ID then perf_header__adds_write() fails. A failure of any
other feature simple disables it by calling clear_feat(). I noticed
this asymmetry and wonder why?
Also, is there a reason why HEADER_TRACE_INFO starts with bit 1 instead
of bit 0. Is bit 0 reserved for some reason?
Thanks,
-Robert
--
Advanced Micro Devices, Inc.
Operating System Research Center
next prev parent reply other threads:[~2011-11-30 15:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-30 13:40 [PATCH] perf: make perf.data more self-descriptive (v8) Stephane Eranian
2011-10-04 4:50 ` David Ahern
2011-11-29 18:22 ` Robert Richter
2011-11-29 18:35 ` Stephane Eranian
2011-11-30 15:08 ` Robert Richter [this message]
2011-11-30 16:49 ` acme
2011-12-01 15:01 ` Frederic Weisbecker
2011-12-01 15:15 ` Robert Richter
2011-12-01 17:53 ` Stephane Eranian
2011-12-05 13:23 ` Robert Richter
2011-12-05 19:24 ` Stephane Eranian
2011-12-06 9:29 ` Robert Richter
[not found] ` <CABPqkBRbdJ0tG2+V-CvEdPnwm5YqQuv7FKrUHoTM8=wa8V=kHQ@mail.gmail.com>
2011-12-19 9:26 ` Robert Richter
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