linux-kernel - Re: [PATCH 0/3] Hook up powerclamp with PM QOS and cpuidle

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 27 Nov 2013 12:56:34 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc:	Linux PM <linux-pm@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Rafael Wysocki <rafael.j.wysocki@...el.com>,
	Len Brown <len.brown@...el.com>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Zhang Rui <rui.zhang@...el.com>
Subject: Re: [PATCH 0/3] Hook up powerclamp with PM QOS and cpuidle

On Tue, Nov 26, 2013 at 03:20:08PM -0800, Jacob Pan wrote:
> This patchset is intended to address the behavior change and efficiency
> loss introduced by using consolidated idle routine in powerclamp driver.
> 
> Specifically,
> [PATCH 3/8] idle, thermal, acpi: Remove home grown idle implementations
> 
> The motivation is that after using common idle routine, powerclamp driver
> can no longer pick the deepest idle state needed to conserve power.
> Idle state is selected by governors which can be influenced by PM QOS and
> other factors. This patchset hooks up powerclamp idle injection with PM
> QOS and eventually influce idle governors to pick the power saving target
> states.
> 
> There are some downside of this approach. Due to overhead, communication
> with PM QOS is at enable/disable idle injection time instead of each
> injection period. The implication is that if the system natual idle is
> more than target injected idle, powerclamp will skip some injection period.
> During this period however, deepest idle state may still be chosen
> necessarily regardless the latency constraint.

Does the QoS stuff have a means of notifying its users of constraints
violation? I suspect some applications might light to be told if their
requests aren't honoured.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/