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From: Justin Piszcz <jpiszcz@lucidpixels.com>
To: Al Boldi <a1426z@gawab.com>
Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
	xfs@oss.sgi.com
Subject: Re: Linux Software RAID 5 Performance Optimizations: 2.6.19.1: (211MB/s read & 195MB/s write)
Date: Fri, 12 Jan 2007 14:56:00 -0500 (EST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0701121455550.6844@p34.internal.lan> (raw)
In-Reply-To: <200701122235.30288.a1426z@gawab.com>



On Fri, 12 Jan 2007, Al Boldi wrote:

> Justin Piszcz wrote:
> > RAID 5 TWEAKED: 1:06.41 elapsed @ 60% CPU
> >
> > This should be 1:14 not 1:06(was with a similarly sized file but not the
> > same) the 1:14 is the same file as used with the other benchmarks.  and to
> > get that I used 256mb read-ahead and 16384 stripe size ++ 128
> > max_sectors_kb (same size as my sw raid5 chunk size)
> 
> max_sectors_kb is probably your key. On my system I get twice the read 
> performance by just reducing max_sectors_kb from default 512 to 192.
> 
> Can you do a fresh reboot to shell and then:
> $ cat /sys/block/hda/queue/*
> $ cat /proc/meminfo
> $ echo 3 > /proc/sys/vm/drop_caches
> $ dd if=/dev/hda of=/dev/null bs=1M count=10240
> $ echo 192 > /sys/block/hda/queue/max_sectors_kb
> $ echo 3 > /proc/sys/vm/drop_caches
> $ dd if=/dev/hda of=/dev/null bs=1M count=10240
> 
> 
> Thanks!
> 
> --
> Al
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Ok. sec

  reply	other threads:[~2007-01-12 19:56 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-11 23:38 Justin Piszcz
2007-01-12 14:01 ` Michael Tokarev
2007-01-12 14:38   ` Justin Piszcz
2007-01-12 17:37     ` Justin Piszcz
2007-01-12 19:49       ` Al Boldi
2007-01-12 19:56         ` Justin Piszcz [this message]
2007-01-12 20:15           ` Justin Piszcz
2007-01-12 20:41             ` Bill Davidsen
2007-01-12 21:00             ` Al Boldi
2007-01-12 21:40               ` Justin Piszcz
2007-01-13  6:11                 ` Al Boldi
2007-01-13  9:40                   ` Justin Piszcz

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