Re: [patch] voluntary-preempt-2.6.8-rc3-O4

Ingo Molnar
2004-08-10T12:39:37Z

* Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> > another (more remote) possibility is that the timestamp counter gets
> > somehow messed up during MMX ops. Does the ALSA detector use the
> > timestamp counter, or does it only use jiffies? (if it only used jiffies
> > that would give us some robustness since it's an independent
> > time-source.) I suspect 'music indeed skips' isnt a good enough test for
> > this case, given that jackd starts up ...
>
> The standard VIA EPIA boards are 133Mhz SDRAM or 266Mhz DDR, which is
> shared with video and the graphics engine. Could the MMX copier simply
> be eating all the remaining memory bandwidth so that its in fact
> memory not latency ?

it's a 10 msec latency that got measured, for a single page copy (!) -
if it's memory latency then it must be something really bad...

Ingo