Re: 2.6.12 Performance problems

From: Jesper Juhl
Date: Wed Aug 24 2005 - 11:35:38 EST


On 8/24/05, Danial Thom <danial_thom@xxxxxxxxx> wrote:
> --- Patrick McHardy <kaber@xxxxxxxxx> wrote:
>
> > Danial Thom wrote:
> > > I think part of the problem is the continued
> > > misuse of the word "latency". Latency, in
> > > language terms, means "unexplained delay".
> > Its
> > > wrong here because for one, its explainable.
> > But
> > > it also depends on your perspective. The
> > > "latency" is increased for kernel tasks,
> > while it
> > > may be reduced for something that is getting
> > the
> > > benefit of preempting the kernel. So you
> > really
> > > can't say "the price of reduced latency is
> > lower
> > > throughput", because thats simply backwards.
> > > You've increased the kernel tasks latency by
> > > allowing it to be pre-empted. Reduced latency
> > > implies higher efficiency. All you've done
> > here
> > > is shift the latency from one task to
> > another, so
> > > there is no reduction overall, in fact there
> > is
> > > probably a marginal increase due to the
> > overhead
> > > of pre-emption vs doing nothing.
> >
> > If instead of complaining you would provide the
> > information
> > I've asked for two days ago someone might
> > actually be able
> > to help you.
>
> Because gaining an understanding of how the
> settings work is better than having 30 guys
> telling me to tune something that is only going
> to make a marginal difference. I didn't ask you
> to tell me what was wrong with my setup, only
> whether its expected that 2.6 would be less
> useful in a UP setup than 2.4, which I think
> you've answered.
>

I hope you're implying that the answer is; no, it's not expected that
2.6 is less useful in a UP setup than 2.4 :-)

--
Jesper Juhl <jesper.juhl@xxxxxxxxx>
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