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

[Bill Davidsen <davidsen@tmr.com>]

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