linux-kernel - Re: [PATCH V5 0/9] perf: Driver specific configuration for PMU

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Date:   Mon, 22 Aug 2016 18:15:56 +0300
From:   Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>, peterz@...radead.org
Cc:     acme@...nel.org, jolsa@...nel.org, mingo@...hat.com,
        vince@...ter.net, mtk.manpages@...il.com,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V5 0/9] perf: Driver specific configuration for PMU

Mathieu Poirier <mathieu.poirier@...aro.org> writes:

> As such something that used to be a two-step process:
>
> # echo 1 > /sys/bus/coresight/devices/20070000.etr/enable_sink
> # perf record -e cs_etm//u --per-thread  uname
>
> is integrated in a single command:
>
> # perf record -e cs_etm/@...k=20070000.etr/u --per-thread  uname

Can't we simply teach perf record to write 1 to that sysfs attribute and
avoid parsing more ascii strings in the kernel? I suspect that would also
take way less code.

Are there any other use cases for this besides specifying @sink for a
ETM?

Regards,
--
Alex