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Date:   Tue, 26 Oct 2021 21:13:31 +0900
From:   Masami Hiramatsu <mhiramat@kernel.org>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Li Zhijian <lizhijian@cn.fujitsu.com>, <mingo@redhat.com>,
        <shuah@kernel.org>, <linux-kselftest@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, Philip Li <philip.li@intel.com>,
        kernel test robot <lkp@intel.com>
Subject: Re: [PATCH] kselftests: ftrace: limit the executing time by reading
 from cached trace
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On Mon, 25 Oct 2021 22:17:17 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Thu, 21 Oct 2021 09:31:31 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > > > +# Stop tracing while reading the trace file by default, to prevent
> > > > +# the test results while checking it and to avoid taking a long time
> > > > +# to check the result.
> > > > +    [ -f options/pause-on-trace ] && echo 1 > options/pause-on-trace
> > > > +  
> > > 
> > > Is there a way we can save the previous setting and put it back on reset?  
> > 
> > No, since each testcase must be run under the clean state. Would we need to
> > recover the settings?
> 
> I would at least put it back to the default. If someone runs the tests,
> it should at least put it back to what it was at boot. Otherwise,
> someone might run the tests, and then wonder why events are being
> dropped when they are reading the trace.

Umm, we may need to have a knob to reset the ftrace options...
Can we warn such user that if the ftracetest finds that the current
value is not the same what it sets?

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>