19 Dec
2003
19 Dec
'03
12:42 p.m.
On Fri, 2003-12-19 at 15:34, Mark Knecht wrote:
I had a dual-processor system until it died about 3 weeks ago. It
definitely didn't have this problem, even though it's using physically
the same SCSI controller and disk. Well, it had a 64bit PCI slot for the
controller. OK, I've upgraded to 2.6 since then, in a partially
successful attempt to reduce the extent of the dropouts.
What are the
other options? I've looked at PCI latencies for card and
drive controller, IRQ ordering (although APIC seems to make this
irrelevant, or at least uncontrollable), OS disk scheduler
(anticipatory, deadline and cfq), tagged queueing (high values almost
guarantee xruns on recording but don't seem to improve playback).
Sheesh, at this rate if I get another dual-processor machine, I'll be
able to run jackd at -p 16 -n 2 :-|
A dual-processor system won't necessarily change a disk latency problem. Have you tried running with larger buffers? Sorry but
I don't have the
original post. Try -p 2048 -n 2 or -p 1024 -n 2 or -p 512 -n 4/8/16 if
your card accepts it and see what happens. Possibly there is just a
better setting to be using.
Still happens, but less, at -p 2048 -n 2 which is the largest the card
will accept.
Also, have you run Benno's latency test app?
It's good at showing
problems like other apps stepping in and causing problems somewhere, and
it can guide you towards the best -p/-n settings.
Yip, 0 overruns on all tests at 2x128.
Real headscratcher, innit?
bye
John