Am Montag 23 Juni 2008 schrieb Martin Steigerwald:
> Am Montag 23 Juni 2008 schrieb Mark:
> > I ran a round of tests using 5 threads, to resemble 1 runnable and 1
> > waiting on each CPU, plus 1 more waiting. In other words, lightly
> > overloaded. XFS was the clear winner, with 378 MB/sec using the
> > "noop" scheduler. The "deadline" scheduler was a close second, with
> > 371 MB/sec.
> > Here was the first twist: The completely fair queueing (CFQ)
> > scheduler seriously impeded XFS performance, so badly that even
> > "noop" out-performed it when the CPU was running at 40% clock.
> > I re-ran all tests with 20 threads, to simulate severe process I/O
> > overloading. Even on my 2-CPU system, XFS scaled somewhat, achieving
> > 403 MB/sec with "deadline" and 401 MB/sec with "anticipatory." CFQ
> > didn't hurt the throughput as much this time, but it still came in
> > last (263 MB/sec).
> Thats interesting. I was curious and thus switched from cfq to deadline
> scheduler during parallel I/O workload on my ThinkPad T42 (aptitude
> upgrade / kmail receiving mails from POP3 account).
> It subjectively feeled way faster with deadline. I always wondered
> about the slowness of my ThinkPad T42 at massive parallel I/O. Now it
> feels a lot more responsive. Its as if I bought a new super-seek
> harddisk or what (compared to before).
It feels like I have a completely different system. Not only on massive
parallel I/O. Starting OpenOffice... starting KDE apps... deadline seems
to outperform cfq regarding subjectively perceived desktop performance to
no end. That difference is absolutely astonishing for me. My ThinkPad
*flies* compared to before.
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7