Subject: Re: [linux-audio-dev] interesting 2.3.4* kernel statistic
From: Roger Larsson (roger.larsson_AT_norran.net)
Date: ti helmi 22 2000 - 16:48:23 EST
Juhana Sadeharju wrote:
>
> >From: Roger Larsson <roger.larsson_AT_norran.net>
> >
> >I.e with the version tested your worst case will be at least 34 ms.
> >Since several locks might be taken during one kernel operation.
>
> This means MS Windows is better platform for audio with 20 ms latency?!
> And Linux has 34 ms minimum latency?!
>
> If that is not true, please tell slowly what this all _really_ means.
> I wonder what was the point of low latency pathes if the situation
> is really that bad as you say.
>
> I really wonder does Linus kernel authors really know what they are doing.
>
> Juhana
Note: The tested system is (most likely) an unpatched system. When Benno
started to look into this summer-99 we measured times like 4000ms !!!
Check his page:
http://www.gardena.net/benno/linux/audio
Start in the bottom and work upwards.
After some arguing with kernel developers I got Andrea to look into it.
His patch improved it a little. But it did improve enough to make
Ingo interested.
That is why we have a lowlatency patch for 2.2.x
To release something like that for 2.3.x is more complicated - why?
Since it has been unstable by itself, but several of the rewrites
for 2.3.x has been done with latency in mind.
Ingo has claimed that he has a working 2.3.x patch at his computer
that will be integrated into 2.3.x when there is fewer other problems.
Ingo: when???
Summary: you do not want to add a patch like this to a unstable kernel.
check out the linux-kernel list too see the problems it causes in a
stable one 2.2.x (There is quite a lot of attention around the
2.2.x patches currently). And Ingo knows exactly what he is doing in
not releasing it before 2.3.x stabilizes.
/RogerL
-- Home page: http://www.norran.net/nra02596/
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