[linux-audio-user] Re: Low Latency patches and kernel 2.6.x

[Florian Schmidt]

On Mon, 22 Dec 2003 11:58:54 -0800
Andrew Morton <akpm at osdl.org> wrote:

Ok, it seems that the list only takes mails from subscribers. sorry for
that.. This mail will let the others see your answer. Thanks for taking
the time. I will do some testing with 2.6. I will report back to you how
it goes [after the holidays]. Have a nice xmas :)

> Florian Schmidt <mista.tapas at gmx.net> wrote:
> >
> > 
> > Hi Andrew,
> > 
> > i'm a user of a 2.4.22 kernel patched with the preemption patches
> > plus your Low Latency patches. It works very nicely for audio
> > applications[like jackd, ardour, etc...].
> 
> Cool.
> 
> > Looking into the config menu of the 2.6.0 kernel i only find a
> > "preemptible kernel" config option. Your low latency patches seem
> > not to be included. Do you have plans of including your patches in
> > the 2.6.x kernel? I heard rumors about merging the preemptible and
> > your LL patches since they seem to go very nicely together.. Any
> > truth to that?
> 
> The objective in 2.6 is that the preemptible kernel achieve similar
> worst-case latencies to the low-latency-patched kernel.  So 2.6 should
> meet your requirements out of the box.
> 
> 
> That being said, last time I instrumented the 2.6 kernel it was not
> achieving the targets.  The specific failure was occurring when the
> machine had a very large number of inodes in cache and the VM system
> was reclaiming those inodes.
> 
> It is unlikely that you will strike this problem in real-world usage,
> so 2.6 should work fine for you.  As ever, testing results would be
> appreciated.
> 
> (The inode reclaim problem is fairly complex, but I just happen to see
> a patch from Dipankar Sarma in my inbox this morning which is designed
> to fix it up).
> 


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