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Date:   Thu, 28 Nov 2019 15:04:25 +0000
From:   Changbin Du <changbin.du@gmail.com>
To:     Andi Kleen <ak@linux.intel.com>
Cc:     Changbin Du <changbin.du@gmail.com>, Jiri Olsa <jolsa@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Namhyung Kim <namhyung@kernel.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 0/2] perf: add support for logging debug messages to
 file
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References: <20191126143720.10333-1-changbin.du@gmail.com>
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On Tue, Nov 26, 2019 at 12:19:11PM -0800, Andi Kleen wrote:
> Changbin Du <changbin.du@gmail.com> writes:
> 
> > When in TUI mode, it is impossible to show all the debug messages to
> > console. This make it hard to debug perf issues using debug messages.
> > This patch adds support for logging debug messages to file to resolve
> > this problem.
> 
> This was already solved in
> 
> commit f78eaef0e0493f6068777a246b9c4d9d5cf2b7aa
> Author: Andi Kleen <ak@linux.intel.com>
> Date:   Fri Nov 21 13:38:00 2014 -0800
> 
>     perf tools: Allow to force redirect pr_debug to stderr.
> 
>     When debugging the tui browser I find it useful to redirect the
>     debug
>         log into a file. Currently it's always forced to the message
>     line.
> 
>     Add an option to force it to stderr. Then it can be easily
>     redirected.
>     
> You can do
> 
> perf report --debug stderr 2> file ...
>
Yes, this is a good alternate approach with existing code. I still think
a new option 'file' is not bad. And later maybe we can ouput debug messages
to file only while errors ouput to both.

> -Andi

-- 
Cheers,
Changbin Du