Saul wrote:
> > > > I thought SMI was supposed to increase latencies, but I only see
> > > > latencies < 60us at any load, unless I start video capture. Does
> > > > the latency test absolutely rule out SMI as the cause?
> > >
> > > Not really, e.g. if the video capture device is USB-attached, then
> > > SMI could possibly remain in the picture.
> >
> > I have used the bttv driver with xawtv or mythtv and nvidia
> > proprietary drivers on a dual pIII machine running latency and the
> > maximum latency was far less than 100 us. What produces large spots,
> > however, is switching virtual terminals or changing resolution.
> > Doesn't xawtv change resolution for full screen mode ? Did not you use
> > the 768x576 modeline hack ?
>
>
> The video capture is not USB, it's a PCI card. Since I don't see poor
> latencies I'm guessing my problem is *not* SMI related.
The latencies above 100us that you observe when starting video capture
are abnormal. I was suggesting that these latencies are not due to video
capture but to the fact that xawtv change resolution. Big latencies
when switching virtual terminal are a well-known issue, not related to
SMI. So my question was: is xawtv configured on your machine to change
resolution when starting capture ?
--
Gilles Chanteperdrix.
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