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From:   Vinicius Costa Gomes <vinicius.gomes@intel.com>
To:     Jiri Olsa <jolsa@redhat.com>
Cc:     Adrian Hunter <adrian.hunter@intel.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Clark Williams <williams@redhat.com>,
        linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        David Ahern <dsahern@gmail.com>, Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Wang Nan <wangnan0@huawei.com>
Subject: Re: [PATCH 11/11] perf tools: Stop fallbacking to kallsyms for vdso symbols lookup
In-Reply-To: <20181027110541.GA25072@krava>
References: <20181017225501.32150-1-acme@kernel.org> <20181017225501.32150-12-acme@kernel.org> <4c682937-3cee-6974-0970-68610e13ad37@intel.com> <87a7n070tj.fsf@intel.com> <20181027110541.GA25072@krava>
Date:   Sat, 27 Oct 2018 13:09:44 -0700
Message-ID: <87bm7fgnhz.fsf@intel.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Jirka,

Jiri Olsa <jolsa@redhat.com> writes:

> On Fri, Oct 26, 2018 at 04:19:52PM -0700, Vinicius Costa Gomes wrote:
>> Hi,
>> 
>> Adrian Hunter <adrian.hunter@intel.com> writes:
>> 
>> > On 18/10/18 1:55 AM, Arnaldo Carvalho de Melo wrote:
>> >> From: Arnaldo Carvalho de Melo <acme@redhat.com>
>> >> 
>> >> David reports that:
>> >> 
>> >> <quote>
>> >> Perf has this hack where it uses the kernel symbol map as a backup when
>> >> a symbol can't be found in the user's symbol table(s).
>> >
>> > I don't think this is a complete fix because it exposes new problems.
>> 
>> This commit broke function name resolution for 'perf record -g' for me.
>> 
>> What I mean is, with this commit applied:
>> 
>> $ ./tools/perf/perf record -g -- sleep 1
>> 
>> $ ./tools/perf/perf report
>> 
>> 'perf report' doesn't seem to be able to show the function names of the
>> trace.
>> 
>> If I revert this commit, function names are resolved fine.
>
> that commit just showed up some places where we have the
> ip resolve wrong.. would attached patch fix it for you?

Thank you for your patch.

I can some difference in the output, but I wouldn't say that it's fixed.

Here are some samples, if it's useful somehow:

https://gist.github.com/vcgomes/985626705e0968b973e426964f86a4b0

The "ping" tests were done running

$ sudo ./tools/perf/perf record -g -- ping -f -c 1000 127.0.0.1

And the "sleep" tests were done running

$ sudo ./tools/perf/perf record -g -- /bin/sleep 1


--
Vinicius