All of lore.kernel.org
 help / color / mirror / Atom feed
From: Arjan van de Ven <arjan@linux.intel.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>,
	Youquan Song <youquan.song@intel.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@zytor.com,
	akpm@linux-foundation.org, stable@vger.kernel.org,
	len.brown@intel.com, anhua.xu@intel.com, chaohong.guo@intel.com,
	Youquan Song <youquan.song@linux.intel.com>
Subject: Re: [PATCH] x86,sched: Fix sched_smt_power_savings totally broken
Date: Tue, 10 Jan 2012 06:32:16 -0800	[thread overview]
Message-ID: <4F0C4BF0.9090809@linux.intel.com> (raw)
In-Reply-To: <20120110091805.GA28024@elte.hu>

On 1/10/2012 1:18 AM, Ingo Molnar wrote:
> 
> * Suresh Siddha <suresh.b.siddha@intel.com> wrote:
> 
>> On Tue, 2012-01-10 at 00:58 -0500, Youquan Song wrote:
>>> Thanks Peter! Here is the patch. 
>>
>> Youquan, As far as I know both the
>> sched_smt_power_savings/sched_mc_power_savings are broken for atleast an
>> year.
> 
> We want a single knob, sched_power_savings - with the mc_ and 
> smt_ ones still kept and aliased to sched_power_savings, for 
> compatibility reasons.
> 
> As Peter said, the other reasonable option is to have no knob at 
> all and restart this code from scratch.
> 
> The other thing we should do is to add sane defaults: to turn on 
> sched_power_savings *AUTOMATICALLY* when a system is obviously 
> battery driven and turn it off when the system is obviously AC 
> driven. User-space can still implement policy and override the 
> kernel's default, but there's absolutely no excuse to not offer 
> this default ourselves.

a very good default would be to keep all tasks on one package until half
the cores in the package are busy, and then start spreading out.

I suspect that'll be the 90% case coverage.

  reply	other threads:[~2012-01-10 14:32 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-09  8:56 [PATCH] x86,sched: Fix sched_smt_power_savings totally broken Youquan Song
2012-01-09 10:06 ` Peter Zijlstra
2012-01-09 10:28   ` Peter Zijlstra
2012-01-09 10:30     ` Peter Zijlstra
2012-01-09 11:00     ` Vaidyanathan Srinivasan
2012-01-09 14:35       ` Peter Zijlstra
2012-01-09 16:03         ` Vaidyanathan Srinivasan
2012-01-09 16:13           ` Peter Zijlstra
2012-01-09 17:05             ` Vaidyanathan Srinivasan
2012-01-09 14:13     ` Arjan van de Ven
2012-05-18 10:19     ` [tip:sched/core] sched: Remove stale power aware scheduling remnants and dysfunctional knobs tip-bot for Peter Zijlstra
2012-01-10  0:14   ` [PATCH] x86,sched: Fix sched_smt_power_savings totally broken Youquan Song
2012-01-09 11:05     ` Peter Zijlstra
2012-01-10  5:58       ` Youquan Song
2012-01-09 23:52         ` Suresh Siddha
2012-01-10  9:18           ` Ingo Molnar
2012-01-10 14:32             ` Arjan van de Ven [this message]
2012-01-10 14:41               ` Peter Zijlstra
2012-01-10 14:54                 ` Arjan van de Ven
2012-01-10 15:32               ` Vincent Guittot
2012-01-10 15:32                 ` Vincent Guittot
2012-01-10 16:49               ` Vaidyanathan Srinivasan
2012-01-10 19:41               ` Ingo Molnar
2012-01-10 19:44                 ` Ingo Molnar
2012-01-10 16:54           ` Youquan Song
2012-01-10 16:51             ` Vaidyanathan Srinivasan
2012-01-10 19:01               ` Suresh Siddha
2012-01-11  3:52                 ` Vaidyanathan Srinivasan
2012-01-11 17:37                   ` Youquan Song
2012-01-10 16:44       ` Vaidyanathan Srinivasan
2012-01-09 11:12     ` Peter Zijlstra
2012-01-09 14:29       ` Vincent Guittot
2012-01-09 14:29         ` Vincent Guittot
2012-01-09 14:46         ` Peter Zijlstra
2012-01-10  2:12           ` Indan Zupancic
2012-01-10  9:26             ` Peter Zijlstra
2012-01-10  1:54         ` Suresh Siddha
2012-01-10  8:08           ` Vincent Guittot
2012-01-09 15:37 ` Greg KH

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4F0C4BF0.9090809@linux.intel.com \
    --to=arjan@linux.intel.com \
    --cc=a.p.zijlstra@chello.nl \
    --cc=akpm@linux-foundation.org \
    --cc=anhua.xu@intel.com \
    --cc=chaohong.guo@intel.com \
    --cc=hpa@zytor.com \
    --cc=len.brown@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=stable@vger.kernel.org \
    --cc=suresh.b.siddha@intel.com \
    --cc=tglx@linutronix.de \
    --cc=youquan.song@intel.com \
    --cc=youquan.song@linux.intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.