From: Adrian Hunter <adrian.hunter@intel.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@redhat.com>,
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>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH] perf tools: Fix not finding kcore in buildid cache
Date: Wed, 27 Nov 2013 10:18:22 +0200 [thread overview]
Message-ID: <5295AACE.2080606@intel.com> (raw)
In-Reply-To: <20131126161553.GB7775@gmail.com>
On 26/11/13 18:15, Ingo Molnar wrote:
>
> * Adrian Hunter <adrian.hunter@intel.com> wrote:
>
>> The logic was not looking in the buildid cache for kcore
>> if the host kernel buildid did not match the recorded
>> kernel buildid.
>
> It would be nice to also include the specific failure mode in the
> changelog: exactly how can users run into this. That will be more
> useful to most people reading these changelogs than a more abstract
> bug description.
The preconditions for the problem are that kcore is in the buildid
cache and that the running kernel has a different buildid e.g.
$ perf buildid-list | grep kernel.kallsyms
b18fbe769dea12513028a4287dae02efc1582c29 [kernel.kallsyms]
$ perf record -o /tmp/junk true >/dev/null 2>&1 ; perf buildid-list -i /tmp/junk | grep kernel.kallsyms
504f9fd9328c40714995ce76fe1354c6e90136ce [kernel.kallsyms]
Before the patch:
$ perf script -v >out.txt
build id event received for [kernel.kallsyms]: b18fbe769dea12513028a4287dae02efc1582c29
<SNIP>
Using /home/ahunter/.debug/[kernel.kallsyms]/b18fbe769dea12513028a4287dae02efc1582c29 for symbols
perf script stopped
After the patch:
$ perf script -v >out.txt
build id event received for [kernel.kallsyms]: b18fbe769dea12513028a4287dae02efc1582c29
<SNIP>
Using /home/ahunter/.debug/[kernel.kcore]/b18fbe769dea12513028a4287dae02efc1582c29/2013112617084061/kcore for kernel object code
Using /home/ahunter/.debug/[kernel.kcore]/b18fbe769dea12513028a4287dae02efc1582c29/2013112617084061/kallsyms for symbols
perf script stopped
next prev parent reply other threads:[~2013-11-27 8:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-26 13:19 [PATCH] perf tools: Fix not finding kcore in buildid cache Adrian Hunter
2013-11-26 16:15 ` Ingo Molnar
2013-11-27 8:18 ` Adrian Hunter [this message]
2013-11-27 11:32 ` Ingo Molnar
2013-11-27 11:51 ` Adrian Hunter
2013-11-27 11:52 ` Ingo Molnar
2013-11-27 14:42 ` Arnaldo Carvalho de Melo
2013-11-30 12:53 ` [tip:perf/core] perf symbols: " tip-bot for Adrian Hunter
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