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From: Ingo Molnar <mingo@kernel.org>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: Huang Ying <ying.huang@intel.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	David Howells <dhowells@redhat.com>,
	linux-kernel@vger.kernel.org, lkp@linux.intel.com
Subject: Re: aim7 performance regression by commit 5a50508 report from LKP
Date: Thu, 31 Jan 2013 12:22:52 +0100	[thread overview]
Message-ID: <20130131112252.GB4587@gmail.com> (raw)
In-Reply-To: <20130130093415.GX12678@yliu-dev.sh.intel.com>


* Yuanhan Liu <yuanhan.liu@linux.intel.com> wrote:

> > or whether the lock hold times could be reduced drastically
> 
> I also found one, but it doesn't sound like the one will 
> reduce lock hold times drastically:
>
>    vma_lock_anon_vma() seems covered too much code at
>    expand_up/downwards.
> 
> Well, again, it's quite a tiny optimization for reducing the 
> coverage.

The fundamental problem is I think that there's a single anon 
vma lock for the whole workload, right?

Is that really fundamentally needed, could that be spread out 
perhaps?

( But first we want to see how much of the regression we can fix 
  in an equivalent-locking-patterns fashion - improving locking
  is a separate matter. )

Thanks,

	Ingo

  reply	other threads:[~2013-01-31 11:22 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-29  8:25 Yuanhan Liu
2013-01-29  8:44 ` Ingo Molnar
2013-01-29  9:06   ` Yuanhan Liu
2013-01-29  9:12     ` Ingo Molnar
2013-01-30  9:34       ` Yuanhan Liu
2013-01-31 11:22         ` Ingo Molnar [this message]
2013-02-01 10:53           ` Yuanhan Liu

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