Re: Extreme slowness with xfs [WAS: Re: Slowness with new pc]

From: Justin Piszcz
Date: Tue Nov 25 2008 - 05:46:21 EST




On Tue, 25 Nov 2008, Christoph Hellwig wrote:

On Tue, Nov 25, 2008 at 04:56:24AM -0500, Justin Piszcz wrote:
barriers enabled:

$ time bash -c 'tar xf linux-2.6.27.7.tar; sync'
block 573932: ** Block of NULs **
Total bytes read: 293857280 (281MiB, 1.9MiB/s)

real 2m40.643s
user 0m0.194s
sys 0m1.541s

barriers disabled:

time bash -c 'tar xf linux-2.6.27.7.tar; sync'
block 573932: ** Block of NULs **
Total bytes read: 293857280 (281MiB, 11MiB/s)

real 0m27.612s
user 0m0.182s
sys 0m1.617s

That's worse than usual, and even the no-barriers numbers are still
really bad. What kind of disk and controller is this? Did you
try to disable the cache with hdparm and see what that gives?


WD 750G on ICH7

Device Model: WDC WD7500AAKS-00RBA0
00:1f.2 SATA controller: Intel Corporation 82801GR/GH (ICH7 Family) SATA AHCI Controller (rev 01)

I've not tried playing with the cache.

Justin.
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