Bug#441847: linux-image-2.6.21-2-486: poor via sata performance

[Michal Suchanek <hramrach@centrum.cz>]

2009/8/14 Moritz Muehlenhoff <jmm@inutil.org>:
> On Tue, Sep 11, 2007 at 02:52:15PM +0000, Debian Live user wrote:
>> Package: linux-image-2.6.21-2-486
>> Version: 2.6.21-6
>> Severity: normal
>>
>>
>> I put several drives into a computer to zero them. With hdparm -t -T the
>> sata drives appear to be the fastest but when writing urandom to all
>> drives in parallel the order of speed observed is
>> 1) USB2 fastest
>> 2) IDE master (slightly slower than USB when the same drive connected)
>> 3) IDE slave (slightly slower than master)
>> 4) SATA ( *MUCH* slower than either IDE or USB although much faster
>> drive connected)
>
> Did the performance inprove with more recent kernels?
>

I was mostly concerned with relative performance - or the scheduling
of writes between the different drives. Since the bottleneck would be
the CPU in this case the total data written per second should be about
the same.

I should probably try with an USB drive as well to be sure but at
least writing to an IDE drive does not stop SATA drive from receiving
data with 2.6.26 kernel.

Thanks

Michal