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From: Dave Chinner <david@fromorbit.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Matt B <jackdachef@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	xfs@oss.sgi.com
Subject: Re: [regression v4.0-rc1] mm: IPIs from TLB flushes causing significant performance degradation.
Date: Thu, 5 Mar 2015 10:51:26 +1100	[thread overview]
Message-ID: <20150304235126.GB18360@dastard> (raw)
In-Reply-To: <20150304233544.GA24733@gmail.com>

On Thu, Mar 05, 2015 at 12:35:45AM +0100, Ingo Molnar wrote:
> 
> * Dave Chinner <david@fromorbit.com> wrote:
> 
> > > After going through the series again, I did not spot why there is 
> > > a difference. It's functionally similar and I would hate the 
> > > theory that this is somehow hardware related due to the use of 
> > > bits it takes action on.
> > 
> > I doubt it's hardware related - I'm testing inside a VM, [...]
> 
> That might be significant, I doubt Mel considered KVM's interpretation 
> of pte details?

I did actaully mention that before:

| I am running a fake-numa=4 config on this test VM so it's got 4
| nodes of 4p/4GB RAM each.

but I think it got snipped before Mel was cc'd.

Perhaps size of the nodes is relevant, too, because the steady state
phase 3 memory usage is 5-6GB when this problem first shows up, and
then continues into phase 4 where memory usage grows again and peaks
at ~10GB....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

  reply	other threads:[~2015-03-04 23:51 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-02  1:04 Dave Chinner
2015-03-02 19:47 ` Linus Torvalds
2015-03-03  1:47   ` Dave Chinner
2015-03-03  2:22     ` Linus Torvalds
2015-03-03  2:37       ` Linus Torvalds
2015-03-03  5:20         ` Dave Chinner
2015-03-03  6:56           ` Linus Torvalds
2015-03-03 11:34             ` Dave Chinner
2015-03-03 13:43               ` Mel Gorman
2015-03-03 21:33                 ` Dave Chinner
2015-03-04 20:00                   ` Mel Gorman
2015-03-04 23:00                     ` Dave Chinner
2015-03-04 23:35                       ` Ingo Molnar
2015-03-04 23:51                         ` Dave Chinner [this message]
2015-03-02 19:17 Matt
2015-03-02 19:25 ` Dave Hansen
2015-03-02 19:45   ` Matt

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