[linux-audio-dev] DRI + Jack conflict?

Dave Robillard drobilla at connect.carleton.ca
Tue Feb 10 23:32:33 UTC 2004


On Tue, 2004-02-10 at 16:51, Chris Pickett wrote:
> Paul Davis wrote:
> >>On Mon, Feb 09, 2004 at 07:32:35PM -0500, Paul Davis wrote:
> >>
> >>>its a basic problem with real time software, the POSIX API etc.
> >>>JACK tries to lock *all* the process memory. 
> >>
> >>This is to ensure that nothing gets swapped out, right ?
> >>Else it is very hard to ensure real time performance ?
> >>(sorry for being somewhat ignorant in this matter).
> > 
> > 
> > well, swapping is one aspect. page faults are the other. either way,
> > yes,  we need to ensure that real-time code is never stalled waiting
> > for data to be bought into memory from disk storage.
> 
> What are the factors influencing the amount of memory the JACK process 
> needs?
> 
> Maybe it's possible to reduce it.
> 
> Unless I misread what you wrote and by "*all* the process memory" you 
> mean the memory of all processes on the system and not just JACK.

For the record, since I started this whole thing, I have 512MB of RAM,
and it's usually well over half free.  (ie I still get that problem when
I have hundreds of megs of free RAM).

But I discovered I'm having not-jack-related DRI problems to begin with,
so when I figure those out I'll see if there is indeed a conflict or if
it's just my screwy system.

When I figure it out, I'll post the verdict for future generations.

-Dave




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