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From: Markus Trippelsdorf <markus@trippelsdorf.de>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org
Subject: Re: isolate_freepages_block(): very high intermittent overhead
Date: Thu, 6 Nov 2014 12:53:22 +0100	[thread overview]
Message-ID: <20141106115322.GA17467@x4> (raw)
In-Reply-To: <545B5E90.6070902@suse.cz>

On 2014.11.06 at 12:42 +0100, Vlastimil Babka wrote:
> On 10/28/2014 09:59 AM, Markus Trippelsdorf wrote:
> > On 2014.10.27 at 23:01 +0100, Vlastimil Babka wrote:
> >> On 10/27/2014 09:40 PM, Markus Trippelsdorf wrote:
> >> > On my v3.18-rc2 kernel isolate_freepages_block() sometimes shows up very
> >> > high (>20%) in perf top during the configuration phase of software
> >> > builds. It increases build time considerably.
> >> > 
> >> > Unfortunately the issue is not 100% reproducible, because it appears
> >> > only intermittently. And the symptoms vanish after a few minutes.
> >> 
> >> Does it happen for long enough so you can capture it by perf record -g ?
> > 
> > It only happens when I use the "Lockless Allocator":
> > http://locklessinc.com/downloads/lockless_allocator_src.tgz
> > 
> > I use: LD_PRELOAD=/usr/lib/libllalloc.so.1.3 when building software,
> > because it gives me a ~8% speed boost over glibc's malloc.
> 
> I tried the allocator while updating my gentoo desktop with 3.18-rc3 and adding
> some extra memory pressure, but didn't observe anything like this. It could be
> system specific. If you do't have the time to debug, can you at least send me
> output of "cat /proc/zoneinfo"?

I will try to debug this further this weekend.
BTW there is an interesting thread on LKML that might be related to this
issue: https://lkml.org/lkml/2014/11/4/904

-- 
Markus

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      reply	other threads:[~2014-11-06 11:53 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-27 20:40 isolate_freepages_block(): very high intermittent overhead Markus Trippelsdorf
2014-10-27 21:06 ` Markus Trippelsdorf
2014-10-27 22:01 ` Vlastimil Babka
2014-10-28  8:59   ` Markus Trippelsdorf
2014-10-29 15:08     ` Vlastimil Babka
2014-11-06 11:42     ` Vlastimil Babka
2014-11-06 11:53       ` Markus Trippelsdorf [this message]

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