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From: Mel Gorman <mgorman@suse.de>
To: PINTU KUMAR <pintu_agarwal@yahoo.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [Query] Performance degradation with memory compaction (on QC chip-set)
Date: Mon, 13 May 2013 09:40:08 +0100	[thread overview]
Message-ID: <20130513084008.GO11497@suse.de> (raw)
In-Reply-To: <1368414026.58026.YahooMailNeo@web160103.mail.bf1.yahoo.com>

On Sun, May 12, 2013 at 08:00:26PM -0700, PINTU KUMAR wrote:
> Dear Mel Gorman,
> 
> I have one question about memory compaction.
> Kernel version: kernel-3.4 (ARM)
> Chipset: Qual-Comm MSM8930 dual-core.
> 
> We wanted to enable CONFIG_COMPACTION for our product with kernel-3.4.
> But QC commented that, enabling compaction on their chip-set is causing performance degradation for some streaming scenarios (from the beginning).
> 
> I wanted to know is this possible always?
> We used compaction with exynos processor and did not observe any performance degradation.
> 

I suspect one of their drivers are using high-order allocations and
hitting compaction as a result. Compaction is not guaranteed to cause
overhead but if it's in use then the scanning and copying overhead can
cause problems.

> Please let me know your comments.
> It will be helpful to decide on enabling compaction or not.
> 

Depends on workload and drivers.

-- 
Mel Gorman
SUSE Labs

      parent reply	other threads:[~2013-05-13  8:40 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1310394396.24243.YahooMailNeo@web162006.mail.bf1.yahoo.com>
     [not found] ` <20110711145448.GI15285@suse.de>
     [not found]   ` <1310462107.89450.YahooMailNeo@web162007.mail.bf1.yahoo.com>
     [not found]     ` <20110712093510.GB7529@suse.de>
     [not found]       ` <1310484381.60694.YahooMailNeo@web162011.mail.bf1.yahoo.com>
     [not found]         ` <20110712154404.GD7529@suse.de>
     [not found]           ` <1368414026.58026.YahooMailNeo@web160103.mail.bf1.yahoo.com>
2013-05-13  3:03             ` [Query] Performance degradation with memory compaction (on QC chip-set) PINTU KUMAR
2013-05-13  8:40             ` Mel Gorman [this message]

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