On Fri, 2003-12-19 at 19:28, Mark Knecht wrote: > > > > Yip, 0 overruns on all tests at 2x128. > > > > Real headscratcher, innit? > > > > bye > > John > > > > Very perplexing. I've gone back and reread the whole thread. It certainly > seems like you've done all the basics and then much more to debug this. I > doubt anything I write here is actually the root cause and solution, but we > might as well keep trying. Thanks > A few questions did come up for me while reading: > > 1) When you say '0 overruns' above, how did you determine this? I found when > running this test that I'd sometimes get these 'blips' in the scheduling > time that would come close to the breakpoint, but not actually go over. Do > you see anything like that? Yeah, there was a pretty regular series of spikes in white. None of them were closer than, say 10-15% of the total distance. > 2) You said you tried tmpfs. What version of Jack are you using, and did you > recompile Jack to do that test? 0.91.3, I've been updating from CVS every few days since about 3 weeks ago. That was just before 0.90 IIRC. > 3) How are you starting Jack? In a terminal or using qjackctl. I have not > reported this before, but I seem to see more xruns when using qjackctl than > when running Jack in a terminal with the same settings. > 4) What command are you generally using to start Jack? In a terminal. jackd -R -d alsa -d hw:0 -p 256 -n 3 > 5) Since APIC is not necessary on a uni-processor, have you tried disabling > it at boot time? I tried removing the option and recompiling the kernel when I was messing around with IRQ priorities. Didn't seem to make much of a difference so I put it back to APIC and left it there. > 6) Possibly important. You said you had a dual-processor up until a few > weeks ago. I presume that you were using the same sound card in that system? > (Thus eliminating the sound card itself as the culprit.) Were you using the > same hard drive? Same hard drive, same SCSI controller, same sound card. Only difference from that point of view is that the SCSI controller used to be in a 64bit PCI slot. But I can't see that making a huge difference because the throughput from one drive wouldn't even begin to get close to the throughput limits of a 32 bit slot. Well, I'm guessing here. > 7) Have you tried looking at this problem with sessions recorded at > different sample rates? In a conversation with another user the other day he > was telling me he gets more xruns at 44.1K than 48K. Only at 48k - that's all I've got. bye John
