linux-kernel - Re: [regression] cross core scheduling frequency drop bisected to 0c313cb20732

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]

Message-ID: <CAJZ5v0j-5Eva2QReG4LHvyZR-iL5rrrWp-3erdfz-u+5xbwRKA@mail.gmail.com>
Date:	Sat, 9 Apr 2016 14:31:22 +0200
From:	"Rafael J. Wysocki" <rafael@...nel.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Mike Galbraith <umgwanakikbuti@...il.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Doug Smythies <dsmythies@...us.net>,
	Rik van Riel <riel@...hat.com>
Subject: Re: [regression] cross core scheduling frequency drop bisected to 0c313cb20732

On Sat, Apr 9, 2016 at 1:07 PM, Peter Zijlstra <peterz@...radead.org> wrote:
> On Fri, Apr 08, 2016 at 10:59:59PM +0200, Rafael J. Wysocki wrote:
>> On Friday, April 08, 2016 08:50:54 AM Mike Galbraith wrote:
>> > On Fri, 2016-04-08 at 08:45 +0200, Peter Zijlstra wrote:
>> >
>> > > Cute, I thought you used governor=performance for your runs?
>> >
>> > I do, and those numbers are with it thus set.
>>
>> Well, this is a trade-off.
>>
>> 4.5 introduced a power regression here so this one goes back to the previous
>> state of things.
>
> Just for my elucidation; how can gov=performance have a 'power'
> regression?

Because of what is used as the "default" idle state most of the time.

C1 was used before 4.5 and that changed to polling in 4.5.