Re: 2.6.20-rc3 regression? hdparm shows 1/2...1/3 the throughput

From: Stefan Richter
Date: Sat Jan 06 2007 - 14:55:34 EST


Tim Schmielau wrote:
> On Sat, 6 Jan 2007, Stefan Richter wrote:
>
>> Did anybody else notice this? The result of "hdparm -t" under 2.6.20-rc
>> seems to be less than half of what you get on 2.6.19. However, disk I/O
>> did *not* get slower according to bonnie++.
>
> yes. See
> http://lkml.org/lkml/2007/1/2/75
> for the solution.
>
> Tim

Thanks. I should have remembered that.

# hdparm -tT /dev/hda

/dev/hda:
Timing cached reads: 10864 MB in 2.00 seconds = 5440.10 MB/sec
Timing buffered disk reads: 58 MB in 3.06 seconds = 18.94 MB/sec
# cat /sys/block/hda/queue/scheduler
noop anticipatory deadline [cfq]
# echo anticipatory > /sys/block/hda/queue/scheduler
# hdparm -tT /dev/hda

/dev/hda:
Timing cached reads: 10680 MB in 2.00 seconds = 5347.20 MB/sec
Timing buffered disk reads: 148 MB in 3.02 seconds = 49.03 MB/sec

--
Stefan Richter
-=====-=-=== ---= --==-
http://arcgraph.de/sr/
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