[linux-audio-dev] Re: [Jackit-devel] Re: k_jack v0.0.0.5

Steve Harris S.W.Harris at ecs.soton.ac.uk
Wed Jan 22 09:53:01 UTC 2003


On Wed, Jan 22, 2003 at 03:22:42 +0100, Robert Jonsson wrote:
> Atleast I have noticed that performance is worse running with jack than 
> running without it. My evidence is basically running MusE with alsa vs 
> jack output. Running with jack it is much more prone to produce xruns.
> 
> I have not talked so much about this because:
> 
> a) jack is in development

Well, technically, but I regard it as stable in its behaviour. Paul, Kai?
 
> b) I thought it was common knowledge

It seems not :)
 
> c) I thought that because the extra weight(scheduling etc) that jack 
> adds this was perfectly justified.
> My system isn't perfectly tuned and that might be the reason I notice 
> the difference...

It shouldn't be a problem, iwht only a few apps running the overhead is
very small. If by "isn't perfectly tuned" you mean not running SCHED_FIFO
or a patched kernel that its not that supprising, the context switch will
be causing big problems. But, at worst it should just make xruns a bit more
frequent, not go from none to some.

IMHO any runtime xruns at all makes audio software unusable.

- Steve



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