Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch

Bill Davidsen
2004-07-13T22:15:17Z

Benno Senoner wrote:
> Lee Revell wrote:
>
>> On Mon, 2004-07-12 at 19:31, Andrew Morton wrote:
>>
>>
>>>
>>> OK, thanks. The problem areas there are the timer-based route cache
>>> flushing and reiserfs.
>>>
>>> We can probably fix the route caceh thing by rescheduling the timer
>>> after
>>> having handled 1000 routes or whatever, although I do wonder if this
>>> is a
>>> thing we really need to bother about - what else was that machine up to?
>>>
>>>
>>
>>
>> Gnutella client. Forgot about that. I agree, it is not reasonable to
>> expect low latency with this kind of network traffic happening. I am
>> impressed it worked as well as it did.
>>
>>
>
> Why not reasonable ? It is very important that networking and HD I/O
> both don't interfere with low latency audio.
> Think about large audio setups where you use PC hardware to act as
> dedicated samplers, software synthesizers etc.
> Such clusters might be diskless and communicate with a GBit ethernet
> with a high performance file server and
> in some cases lots of network I/O might occur during audio playback. So
> having latency spikes during network I/O
> would be a big showstopper for many apps in certain setups.
> Even ardour if run on a diskless client would need low latency while
> doing network I/O because it does lots of disk I/O
> which on the diskless client translate to lots of network I/O.
> Typical use could be educational or research institutions where diskless
> clients drastically lower the cost of managing large number
> of boxes and allow sharing of resources. See the LTSP project.

Having used "diskless" systems off and on for almost two decades, I
highly suggest that you are better off with a disk in the node, and use
that for swap and temp. If you place any value on the time of people,
this will eliminate a lot of performance (time and bandwidth) issues,
and usually save on the cost of managing, since you have nothing to
manage on the node and a lot less network traffic to handle.

I've done it with SunOS, Solaris and Linux.

--
-bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me