Date: Mon, 12 Nov 2012 09:50:08 +0000
From: Mel Gorman <mgorman@suse.de>
To: Alex Shi <lkml.alex@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, Rik van Riel <riel@redhat.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Ingo Molnar <mingo@kernel.org>, Alex Shi <alex.shi@intel.com>,
        "Chen, Tim C" <tim.c.chen@intel.com>
Subject: Re: [PATCH 00/31] numa/core patches
Message-ID: <20121112095008.GR8218@suse.de>
References: <20121025121617.617683848@chello.nl>
 <20121030122032.GC3888@suse.de>
 <CAGjg+kHrbjr8T0+TOEKp6Mx4zZBbrh_3VPUt81nWj6u3xi=NNQ@mail.gmail.com>
 <20121103122157.GH8218@suse.de>
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On Sat, Nov 10, 2012 at 10:47:41AM +0800, Alex Shi wrote:
> On Sat, Nov 3, 2012 at 8:21 PM, Mel Gorman <mgorman@suse.de> wrote:
> > On Sat, Nov 03, 2012 at 07:04:04PM +0800, Alex Shi wrote:
> >> >
> >> > In reality, this report is larger but I chopped it down a bit for
> >> > brevity. autonuma beats schednuma *heavily* on this benchmark both in
> >> > terms of average operations per numa node and overall throughput.
> >> >
> >> > SPECJBB PEAKS
> >> >                                        3.7.0                      3.7.0                      3.7.0
> >> >                               rc2-stats-v2r1         rc2-autonuma-v27r8         rc2-schednuma-v1r3
> >> >  Expctd Warehouse                   12.00 (  0.00%)                   12.00 (  0.00%)                   12.00 (  0.00%)
> >> >  Expctd Peak Bops               442225.00 (  0.00%)               596039.00 ( 34.78%)               555342.00 ( 25.58%)
> >> >  Actual Warehouse                    7.00 (  0.00%)                    9.00 ( 28.57%)                    8.00 ( 14.29%)
> >> >  Actual Peak Bops               550747.00 (  0.00%)               646124.00 ( 17.32%)               560635.00 (  1.80%)
> >>
> >> It is impressive report!
> >>
> >> Could you like to share the what JVM and options are you using in the
> >> testing, and based on which kinds of platform?
> >>
> >
> > Oracle JVM version "1.7.0_07"
> > Java(TM) SE Runtime Environment (build 1.7.0_07-b10)
> > Java HotSpot(TM) 64-Bit Server VM (build 23.3-b01, mixed mode)
> >
> > 4 JVMs were run, one for each node.
> >
> > JVM switch specified was -Xmx12901m so it would consume roughly 80% of
> > memory overall.
> >
> > Machine is x86-64 4-node, 64G of RAM, CPUs are E7-4807, 48 cores in
> > total with HT enabled.
> >
> 
> Thanks for configuration sharing!
> 
> I used Jrockit and openjdk with Hugepage plus pin JVM to cpu socket.

If you are using hugepages then automatic numa is not migrating those
pages. If you are pinning the JVMs to the socket then automatic numa
balancing is unnecessary as they are already on the correct node.

> In previous sched numa version, I had found 20% dropping with Jrockit
> with our configuration. but for this version. No clear regression
> found. also has no benefit found.
> 

You are only checking for regressions with your configuration which is
important because it showed that schednuma introduced only overhead in
an optimisation NUMA configuration.

In your case, you will see little or not benefit with any automatic NUMA
balancing implementation as the most important pages neiter can migrate
nor need to.

-- 
Mel Gorman
SUSE Labs
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