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* SATA Harddisk speed drop of 100 MB/s
@ 2007-06-20 22:48 Carlo Wood
  2007-06-20 23:06 ` Jeff Garzik
  0 siblings, 1 reply; 32+ messages in thread
From: Carlo Wood @ 2007-06-20 22:48 UTC (permalink / raw)
  To: linux-kernel

hdparm -tT gives over 160 MB/s for my tripple 10k rpm Raptor RAID5
on 2.6.18, as expected.

In 2.6.22-rc5 this dropped to only 60 MB/s !

Is this a known issue?

I also measured it with bonnie; I get 108 MB/s reading speed on
2.6.18 and only 68 MB/s on 2.6.22-rc5.

-- 
Carlo Wood <carlo@alinoe.com>

^ permalink raw reply	[flat|nested] 32+ messages in thread
* Re: SATA Harddisk speed drop of 100 MB/s
@ 2007-06-23  5:26 Al Boldi
  0 siblings, 0 replies; 32+ messages in thread
From: Al Boldi @ 2007-06-23  5:26 UTC (permalink / raw)
  To: linux-kernel

Carlo Wood wrote:
> Just one kernel version? The problem here is in every
> kernel revision after 551c012d7eea3dc5ec063c7ff9c718d39e77634f
>
> 2.6.20-rc2,rc3,rc4,rc5,rc6,rc7 ... 2.6.20 ... 2.6.21 ... 2.6.22-rc5
>
> noop:
>  Timing buffered disk reads:  254 MB in  3.00 seconds =  84.66 MB/sec
>
> anticipatory:
>  Timing buffered disk reads:  252 MB in  3.02 seconds =  83.43 MB/sec
>
> deadline:
>  Timing buffered disk reads:  258 MB in  3.02 seconds =  85.41 MB/sec
>
> cfq:
>  Timing buffered disk reads:  194 MB in  3.03 seconds =  64.06 MB/sec
>
> The normal value is cfq. So, all other schedulars are somewhat faster,
> but still far from the correct 165 MB/s.

You may want to play with /sys/block/*/queue/max_sectors_kb and 
read_ahead_kb.  On my system, setting them to 192 gives best performance, 
but cfq is always slower.


Thanks!

--
Al


^ permalink raw reply	[flat|nested] 32+ messages in thread

end of thread, other threads:[~2007-07-05 22:12 UTC | newest]

Thread overview: 32+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2007-06-20 22:48 SATA Harddisk speed drop of 100 MB/s Carlo Wood
2007-06-20 23:06 ` Jeff Garzik
2007-06-21  3:36   ` Arjan van de Ven
2007-06-22 16:21     ` Carlo Wood
2007-06-22 21:17       ` Henrique de Moraes Holschuh
2007-06-22 21:27         ` Carlo Wood
2007-06-23  1:31           ` Henrique de Moraes Holschuh
2007-06-23  2:59             ` Carlo Wood
2007-06-23 17:29               ` Andrew Morton
2007-06-23 22:21                 ` Jeff Garzik
2007-06-25 15:18               ` Lennart Sorensen
2007-06-25 16:04                 ` Carlo Wood
2007-06-22 21:44   ` SATA RAID5 " Carlo Wood
2007-06-23  3:54     ` Carlo Wood
2007-06-23  6:22       ` Tejun Heo
2007-06-22 21:48   ` Carlo Wood
2007-06-23  7:03     ` Jeff Garzik
2007-06-23  7:54       ` Tejun Heo
2007-06-23 12:53       ` Carlo Wood
2007-06-23 17:30         ` Bartlomiej Zolnierkiewicz
2007-06-23 22:43         ` Jeff Garzik
2007-06-24 11:58           ` Michael Tokarev
2007-06-24 12:59             ` Dr. David Alan Gilbert
2007-06-24 14:21               ` Justin Piszcz
2007-06-24 15:52                 ` Michael Tokarev
2007-06-24 16:59                   ` Justin Piszcz
2007-06-24 22:07                     ` Carlo Wood
2007-06-24 23:46                       ` Mark Lord
2007-06-25  0:23                       ` Patrick Mau
2007-06-24 15:48               ` Michael Tokarev
2007-07-05 22:12             ` Phillip Susi
2007-06-23  5:26 SATA Harddisk " Al Boldi

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