[linux-audio-user] The trouble with disks

Mr. Spock spock at canopus22.demon.co.uk
Sat Dec 20 03:13:31 EST 2003


On Sat, Dec 20, 2003 at 09:41:28AM +0200, John Anderson wrote:
> On Fri, 2003-12-19 at 23:24, Jack O'Quin wrote:
> > John Anderson <ardour at semiosix.com> writes:
> > 
> > > This was on vanilla 2.6.0 with Pre-emptible Kernel turned on, for those
> > > who've been asking.
> > 
> > I'm not surprised, -p256 seems a bit too low for reliable operation
> > with 2.6 on my system.  It runs, but not well.  Personally, I suspect
> > some long paths with preemption disabled in the VM code, just a guess.
> > 
> > What happens with a 2.4 kernel patched for low-latency?
> 
> The reason I moved to 2.6 in the first place was that I was having
> trouble. But just to refresh my memory, I rebooted to 2.4, patched for
> low latency and pre-emptibility, and sure enough, same symptoms. I
> didn't forget to echo 1 >/proc/sys/kernel/lowlatency.
> 
Hmmm, this is getting weirder! I thought last night that your trouble
may have been caused by this:

- There are known performance problems with the default disk I/O scheduler
  which show up when the workload is performing small, random reads and
  writes (ie: database loads).  Largely fixed in -mm.

http://kerneltrap.org/node/view/1816

But this can't be the case if it happened on 2.4.?? also.
Maybe you could benchmark your hard disk, or swap in another drive?

Hope you can get round this one.


Cheers,
Malcolm Smith



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