Re: [linux-audio-dev] Re: costs of IPC

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Subject: Re: [linux-audio-dev] Re: costs of IPC
From: Abramo Bagnara (abramo_AT_alsa-project.org)
Date: Tue May 15 2001 - 20:16:40 EEST

Steve Harris wrote:
>
> On Tue, May 15, 2001 at 05:20:47PM +0200, Abramo Bagnara wrote:
> > >
> > > I'm a little puzzled. the "sp" case doesn't have any IPC costs or
> > > context switches. How can it be consuming 12-15% of the CPU time in
> > > these costs? These costs are always zero for this case, surely?
> >
> > As far as I understand Steve has not plotted the difference but the two
> > CPU usage %. The relative cost of mp approach is the difference between
> > the two values.
>
> Yes. When shared is 0, stack is constant, but not zero, and vica versa. So
> osme work is being done.
>
> I think a 2d graph of shared against stack against cpu use would be
> telling, but it would take a really long time.

Stack is not a lot variable: we can easily make an high esteem in 4 or 8
Kb.

More interesting is shared and perhaps to add by component pollution:
note that in sp each component have to pollute a *different* area.

I don't believe this make some difference, but I'm too ignorant to be
sure.

I'll made some change and I'll try. 

-- 
Abramo Bagnara                       mailto:abramo_AT_alsa-project.org

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy

ALSA project               http://www.alsa-project.org
It sounds good!

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