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From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Mike Galbraith <bitbucket@online.de>, X86 ML <x86@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC] sched: Add a new lockless wake-from-idle implementation
Date: Thu, 13 Feb 2014 10:38:00 +0100	[thread overview]
Message-ID: <20140213093800.GA6078@gmail.com> (raw)
In-Reply-To: <218b548b69479baa005af8a7b04a3abbea8ed6fa.1392252790.git.luto@amacapital.net>


* Andy Lutomirski <luto@amacapital.net> wrote:

> This is a strawman proposal to simplify the idle implementation, eliminate
> a race
> 
> Benefits over current code:
>  - ttwu_queue_remote doesn't use an IPI unless needed

Cool.

>  - The diffstat should speak for itself :)

Neat!

>  - Less racy.  Spurious IPIs are possible, but only in narrow windows or
>    when two wakeups occur in rapid succession.
>  - Seems to work (?)
> 
> Issues:
>  - Am I doing the percpu stuff right?
>  - Needs work on non-x86 architectures

Absolutely, and with the least amount of disruption possible, as 
people are not very good at testing 'all' of them.

>  - The !CONFIG_SMP case needs to be checked

Which also happens to be the default for half of all non-x86 arches.

>  - Is "idlepoll" a good name for the new code?  It doesn't have *that*
>    much to do with the idle state.  Maybe cpukick?

'cpukick', hands down.

> If this turns out okay, TIF_NEED_RESCHED could possibly be deleted as well.

Cool ...

Thanks,

	Ingo

  reply	other threads:[~2014-02-13  9:38 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-11 20:23 Too many rescheduling interrupts (still!) Andy Lutomirski
2014-02-11 21:21 ` Thomas Gleixner
2014-02-11 22:34   ` Andy Lutomirski
2014-02-12 10:13     ` Peter Zijlstra
2014-02-12 15:49       ` Andy Lutomirski
2014-02-12 16:39         ` Peter Zijlstra
2014-02-12 18:19           ` Andy Lutomirski
2014-02-12 20:17             ` Peter Zijlstra
2014-02-13  1:40               ` [RFC] sched: Add a new lockless wake-from-idle implementation Andy Lutomirski
2014-02-13  9:38                 ` Ingo Molnar [this message]
2014-02-13 14:49                 ` Frederic Weisbecker
2014-02-13 14:50                 ` Peter Zijlstra
2014-02-13 17:07                   ` Andy Lutomirski
2014-02-13 20:16                     ` Peter Zijlstra
2014-02-13 20:35                       ` Andy Lutomirski
2014-02-13 19:58                   ` Andy Lutomirski
2014-02-14  1:38                     ` Andy Lutomirski
2014-02-14 20:01                   ` Andy Lutomirski
2014-02-14 20:17                     ` Andy Lutomirski
2014-02-14 21:19                       ` Peter Zijlstra
2014-02-12 15:59       ` Too many rescheduling interrupts (still!) Frederic Weisbecker
2014-02-12 16:43         ` Peter Zijlstra
2014-02-12 17:46           ` Frederic Weisbecker
2014-02-12 18:15             ` Peter Zijlstra

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