linux-kernel - Re: [PATCH] cpufreq: powernv: Export frequency throttle state of the chip through sysfs

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Date:	Thu, 27 Aug 2015 19:31:30 +1000
From:	Michael Ellerman <mpe@...erman.id.au>
To:	Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>
Cc:	rjw@...ysocki.net, stewart@...ux.vnet.ibm.com,
	linux-pm@...r.kernel.org, viresh.kumar@...aro.org,
	linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org
Subject: Re: [PATCH] cpufreq: powernv: Export frequency throttle state of
 the chip through sysfs

On Thu, 2015-08-27 at 14:43 +0530, Shilpasri G Bhat wrote:
> Create a sysfs 'throttle' attribute per-chip(per-numa-node) to reflect
> the throttle state of the chip. The usersapce programs can poll on
> this attribute to keep an eye on the throttle state. Currently we
> print a log message to notify the user of throttling event. The
> performance-sensitive applications can monitor the throttle state
> using this attribute.

Performance sensitive applications can *poll* on a sysfs file, which does a
loop over all chips and potentially spams the console with pr_crit() messages ?

That does not sound like a recipe for success.

What problem are we actually trying to solve here?

cheers



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