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From: Robert Love <rml@tech9.net>
To: akpm@digeo.com
Cc: linux-kernel@vger.kernel.org
Subject: benchmarks of O_STREAMING in 2.5
Date: 16 Oct 2002 22:53:20 -0400	[thread overview]
Message-ID: <1034823201.722.429.camel@phantasy> (raw)

I gave the O_STREAMING in Andrew's 2.5-mm tree the treatment..

Short summary: It works.

The streaming read test in the following benchmarks is simply a read()
in 64KB byte chunks of an 800MB file.

First test.  Show the cache effects are indeed as we intend and the
overhead is negligible.  Here, mem=2G.

	O_STREAMING?	Wall time	Cache Delta
	Yes		21.827s		0
	No		21.734s		+800MB

Second test.  Same deal, but mem=8M.  There was slight swapping, so I
suspect the reduced VM pressure is why the O_STREAMING run is faster.

	O_STREAMING?	Wall time	Cache Delta
	Yes		22.303s		0
	No		28.812s		+1MB

Third and final test. Kernel compile (make -j2) with a couple streaming
reads in the background.  Again, mem=2G.  This shows that actually
saving the pagecache from the horrid waste is useful.

	O_STREAMING	Wall time to complete Kernel compile
	Yes		5m30.494s
	No		4m59.661s

So, uh, Andrew's 2.5 code works ;-)

Someone buy me a dual Xeon,

	Robert Love


             reply	other threads:[~2002-10-17  2:47 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-10-17  2:53 Robert Love [this message]
2002-10-17  7:33 ` benchmarks of O_STREAMING in 2.5 Giuliano Pochini
2002-10-17  7:40   ` Robert Love
2002-10-21 14:38 ` Alan Cox
2002-10-21 14:32   ` Padraig Brady
2002-10-21 16:14     ` Alan Cox
  -- strict thread matches above, loose matches on Subject: below --
2002-10-17 22:59 Dieter Nützel
     [not found] <1034823201.722.429.camel@phantasy.suse.lists.linux.kernel>
     [not found] ` <1035211132.27309.131.camel@irongate.swansea.linux.org.uk.suse.lists.linux.kernel>
2002-10-21 14:35   ` Andi Kleen

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