Re: IO performance problems in 2.4.19-pre5 when writing to DVD-RAM/ZIP/MO

Rik van Riel (riel@conectiva.com.br)
Tue, 16 Apr 2002 13:40:49 -0300 (BRT)


On Tue, 16 Apr 2002, Alan Cox wrote:

> > > benchmarks 1-4, kernel 2.4.19-pre5 performed much worse than
> > > 2.4.18. The reason may be that the main throughput stems from the
> > > short moments where, for what reason whatsoever, read speed increases
>
> Fairness, throughput, latency - pick any two..

Personally I try to go for fairness and latency in -rmap,
since most real workloads I've encountered don't seem to
have throughput problems.

The standard "it's getting slow" complaint has been about
response time and fairness 90% of the time, usually when
the system stalls one process during some other activity.

> > Right fix is different but not suitable for 2.4.
>
> Curious - what do you think the right fix is ?

Tuning the current system for latency and fairness should
keep most people happy. Desktop users really won't notice
if unpacking an RPM takes 20% longer, but having their
mp3 skip during RPM unpacking is generally considered
unacceptable.

regards,

Rik

-- 
	http://www.linuxsymposium.org/2002/
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http://www.surriel.com/ http://distro.conectiva.com/

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