On Fri, 2003-12-19 at 15:34, Mark Knecht wrote: > > 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. 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. > 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
