18 Feb
2006
18 Feb
'06
2:10 p.m.
On Saturday 18 February 2006 18:54, Lee Revell wrote:
On Sat, 2006-02-18 at 00:47 -0800, Kevin Cosgrove
wrote:
I suppose it also work with SATA drives, doesn't it? At
least /sys/block/sda/queue/max_sectors_kb is available here.
I just tried with Ubuntu's dapper's stock 2.6.15 kernel. Jackd runs at 44100Hz
samplerate and buffersize 256 samples (5.8ms periods). Hardware is an AOpen
i915GMm-HFS board with a Pentium M 730 (1.6 GHz) and a RME Digi96/8 PAD.
Default max_sectors_kb is 1024, giving me casual xruns of up to 16 ms on an
idle machine. With max_sectors_kb at 64, xruns reduce to max. 5 ms. Setting
max_sectors_kb smaller than 64 seems to give no further improvement.
So it definitely helps, but not enough to go without -rt for me.
Wolfgang
On 18 February 2006 at 0:15, Lee Revell
<rlrevell(a)joe-job.com> wrote:
It limits the amount of disk IO that can be "in flight" at once, which
limits the amount of work the IDE driver will do in a single interrupt,
which improves the worst case disk IO induced latency.
It's not going to help with an -rt kernel, only mainline.
I'd be interested to see what results people get...
Lee This helps a lot:
echo 64 > /sys/block/hdc/queue/max_sectors_kb
(replace hdc with your drive, repeat for all of them)
Interesting. What does that do?