Subject: Re: [linux-audio-dev] MuCoS: What's going on?
From: Benno Senoner (sbenno_AT_gardena.net)
Date: to tammi 06 2000 - 07:17:29 EST
On Wed, 05 Jan 2000, David Olofson wrote:
> Hi!
>
> Still alive, although it doesn't show much on the MuCoS site... :-(
> Time to get working again!
>
> What's going on with the related project and prototypes? (Benno,
> Paul,...?)
Some time ago I began to experiment with a client/server low-latency
buit ran into troubles (too high latencies, semaphore deadlocks etc).
I am now working on a simple userspace latency-profiling API, which
should give you latency-graphs similar to these produced by "latencytest".
This should help us to better identify where the bottlenecks in
low-latency code are, especially try to optimize the client/server API.
The kernel may require further little refinements (semaphore code etc),
but msgrcv() and msgsnd() seems already promising.
I hope that I can get out soon of the "vaporware" phase and come
up with some real benchmark code to experiment it.
I think as far as it concerns the client/server model ,
the steps to do should be the following:
- finish the latency-profiling API in order to easily get latency-graphs
out of your foobar low-latency app without fiddling with GIF image creation,
timing ( TSC) , allocation of the latency-tables etc. (me)
- use the latency-profiling API to get a sample client/server with decent
performance (me)
- publish the code on this list for peer review to get new ideas or to identify
potential flaws
- integrate the code into Mucos to make an unified API and provide tools
like Paul suggested to simulate /dev/dsp wrappers via LD_PRELOAD
I hope that a preliminary latency API is ready in a few days, then I can begin
to profile the IPC code of the client/server.
PS: Paul good work for your Hammerfall driver !
Benno.
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