(I missed part of this thread. I hope I correcltly deduced that you
guys are talking about the improved disk troughput when increasing the
HZ clock rate ... )
Alan Cox wrote:
> > Why was the rate incremented to maintain interactive performance? Wasn't
> > that the whole idea of the pre-empt work? Does the burden of pre-empt
> > actually require this?
>
> Bizarrely in many cases it increases throughput
IMHO, This is a hint that there is something not quite right with the
scheduler.
This effect has been reported here a couple of times.
If increasing the timer rate improves disk throughput that means that
the disk-reading process is not scheduled immediately following the
disk interrupt, but is somehow left waiting until the next timer
tick....
It should be scheduled "immediately" even if there is another
cpu-eating process: the scheduling heuristics should help there...
Roger.
-- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 ** *-- BitWizard writes Linux device drivers for any device you may have! --* * There are old pilots, and there are bold pilots. * There are also old, bald pilots. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Mon Jul 15 2002 - 22:00:19 EST