Tuning XFS for real time audio on a laptop with encrypted LVM

[Eric Sandeen]

Pedro Ribeiro wrote:
> Hi all,
> 
> I was wondering what is the best scheduler for my use case given my
> current hardware.
> 
> I have a laptop with a fast Core 2 duo at 2.26 and a nice amount of
> ram (4GB) which I use primarily for real time audio (though without a
> -rt kernel). All my partitions are XFS under LVM which itself is
> contained on a LUKS partition (encrypted with AES 128).
> 
> CFQ currently does not perform very well and causes a lot of thrashing
> and high latencies when I/O usage is high. Changing it to the noop
> scheduler solves some of the problems and makes it more responsive.
> Still performance is a bit of a let down: it takes 1m30s to unpack the
> linux-2.6.34 tarball and a massive 2m30s to rm -r.
> I have lazy-count=1, noatime, logbufs=8, logbsize=256k and a 128m log.

Are you optimizing for kernel untars, or "real time audio?"

I would expect that even suboptimal tuning would keep up just fine with
audio demands.

-Eric

> Is there any tunable I should mess with to solve this? And what do you
> think of my scheduler change (I haven't tested it that much to be
> honest)?
> 
> Regards,
> Pedro