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From: Peter Zijlstra <peterz@infradead.org>
To: Alexander Gordeev <agordeev@redhat.com>
Cc: linux-kernel@vger.kernel.org, Kent Overstreet <kmo@daterainc.com>,
	Jens Axboe <axboe@kernel.dk>, Shaohua Li <shli@kernel.org>,
	Nicholas Bellinger <nab@linux-iscsi.org>,
	Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH RFC 0/2] percpu_ida: Take into account CPU topology when stealing tags
Date: Tue, 22 Apr 2014 13:56:29 +0200	[thread overview]
Message-ID: <20140422115629.GI11182@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <cover.1395840483.git.agordeev@redhat.com>

On Wed, Mar 26, 2014 at 02:34:22PM +0100, Alexander Gordeev wrote:
> Hello,
> 
> This series is against 3.14.0-rc7.
> 
> It is amied to further improve 'percpu_ida' tags locality by taking
> into account system's CPU topology when stealing tags. That is try
> to steal from a CPU which is 'closest' to the stealing one.
> 
> I would not bother to post this, since on several system the change
> did not show any improvement, i.e. on such one:

There's is much lower level fruit to be had before doing something like
this.

  https://lkml.org/lkml/2014/1/23/257
  https://lkml.org/lkml/2014/1/23/329
  https://lkml.org/lkml/2014/1/23/343
  https://lkml.org/lkml/2014/1/23/354

I've not had time to revisit/finish them, but you should definitely
clean up the percpu_ida stuff and reduce existing contention before
going overboard.

  parent reply	other threads:[~2014-04-22 19:58 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-26 13:34 [PATCH RFC 0/2] percpu_ida: Take into account CPU topology when stealing tags Alexander Gordeev
2014-03-26 13:34 ` [PATCH RFC 1/2] sched: Introduce topology level masks and for_each_tlm() macro Alexander Gordeev
2014-03-26 13:34 ` [PATCH RFC 2/2] percpu_ida: Use for_each_tlm() macro for CPU lookup in steal_tags() Alexander Gordeev
2014-04-22  7:10 ` [PATCH RFC 0/2] percpu_ida: Take into account CPU topology when stealing tags Alexander Gordeev
2014-04-22 14:03   ` Jens Axboe
2014-04-22 15:57     ` Jens Axboe
2014-04-23  0:53       ` Ming Lei
2014-04-23  1:25         ` Jens Axboe
2014-04-25  9:10           ` Ming Lei
2014-04-25 21:23             ` Jens Axboe
2014-04-26  0:01               ` Ming Lei
2014-04-26  2:03                 ` Jens Axboe
2014-04-29 11:35                   ` Ming Lei
2014-04-29 21:13                     ` Jens Axboe
2014-04-30  9:40                       ` Ming Lei
2014-05-01 22:47                       ` Kent Overstreet
2014-05-02  2:19                         ` Jens Axboe
2014-05-02  2:38                           ` Kent Overstreet
2014-05-02  2:44                             ` Jens Axboe
2014-05-02  5:05                           ` Christoph Hellwig
2014-05-02 16:41                             ` Jens Axboe
2014-05-02 16:43                               ` Christoph Hellwig
2014-05-02 16:56                                 ` Jens Axboe
2014-04-22 11:56 ` Peter Zijlstra [this message]
2014-05-01 21:24   ` Alexander Gordeev
2014-05-01 22:04     ` Alexander Gordeev

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