From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: James Bottomley <James.Bottomley@suse.de>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
Robert Hancock <hancockrwd@gmail.com>,
"Gao, Yunpeng" <yunpeng.gao@intel.com>,
"linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>
Subject: Re: How to make kernel block layer generate bigger request in the request queue?
Date: Mon, 12 Apr 2010 14:26:41 -0400 [thread overview]
Message-ID: <yq1d3y4msri.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <1270911503.2806.194.camel@mulgrave.site> (James Bottomley's message of "Sat, 10 Apr 2010 09:58:23 -0500")
>>>>> "James" == James Bottomley <James.Bottomley@suse.de> writes:
>> Correct. It's quite unlikely for pages to be contiguous so this is
>> the best we can do.
James> Actually, average servers do about 50% contiguous on average
James> since we changed the mm layer to allocate in ascending physical
James> page order ... this figure is highly sensitive to mm changes
James> though, and can vary from release to release.
Interesting. When did this happen?
Last time I gathered data on segment merge efficiency (1 year+ ago) I
found that adjacent pages were quite rare for a normal fs type workload.
Certainly not in the 50% ballpark. I'll take another look when I have a
moment...
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2010-04-12 18:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-09 14:07 How to make kernel block layer generate bigger request in the request queue? Gao, Yunpeng
2010-04-09 23:54 ` Robert Hancock
2010-04-10 2:05 ` Martin K. Petersen
2010-04-10 14:58 ` James Bottomley
2010-04-12 18:26 ` Martin K. Petersen [this message]
2010-04-12 19:58 ` James Bottomley
2010-04-13 15:06 ` Gao, Yunpeng
2010-04-13 15:20 ` Alan Cox
2010-04-19 6:42 ` Gao, Yunpeng
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