7 Jan
2011
7 Jan
'11
9:07 p.m.
On 01/07/2011 08:14 PM, Josh Lawrence wrote:
On Fri, Jan 7, 2011 at 9:03 AM, Robin Gareus
<robin(a)gareus.org> wrote:
I've just read config-2.6.36-2.dmz.8-liquorix-amd64
and no it's not a -rt kernel. It's got PREEMPT but not PREEMPT_RT.
Yet there's not that many differences between the
config-2.6.33.7.2-rt30-multimedia-amd64 (64studio) and liquorix config
otherwise.
The most prominent ones are that liqorix uses "BFQ" instead of "CFQ"
disk scheduling algorithm and "performance" rather than "ondemand"
CPU
governor by default.
On two test systems here CFQ with combined with NCQ yielded lower
latency through slightly less max throughput. But it's a decision to
revisited for 64studio once 2.6.37-rt is out.
There's a few minor things that could be optimized with liquorix.
amongst others e.g. disable CC_STACKPROTECTOR and RELOCATABLE for the
last pinch of perfomance, but maybe better safe than sorry.
BTW. There's no RT patch for 2.6.36.
www.pengutronix.de provides /official/ rt-kernel
for Debian unstable/sid.
deb http://debian.pengutronix.de/debian sid main contrib non-free
If you're on a 64 bit machine. 64studio has a squeeze backport repo
with latest preempt-rt kernel images (called "linux-image-*-multimedia")
deb http://apt.64studio.com/backports squeeze main contrib non-free
linux-image-2.6.33.7.2-rt30-multimedia-amd64 on 64studio.com is being
built as we speak. 2.6.33.7-rt29-multimedia-amd64 is pretty robust.
in addition to Robin's suggestions, I'll add one more to the mix:
AVLinux uses this kernel, I dunno if it is a true -rt kernel , but my
results have been very positive:
http://liquorix.net/
Recent vanilla kernels are fine these days unless you really need
reliable low latency (let's say < 10ms ~ 256*2 fpp @ 48k).
ymmv. my initial reaction would be to trust the 64
studio kernel over
all of the suggestions, just b/c they are familiar with the linux
audio landscape.
--
Robin Gareus
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