On Fri, 2001-10-05 at 03:29, Takashi Iwai wrote: > At 04 Oct 2001 19:21:35 -0700, > Josh Green wrote: > > > > Aggh.. I just ran a whole bunch of ALSA latencytests with various > > drivers/kernels, all with fairly bad results :( I even went back to my > > older kernel (2.4.5 with Andrew Morton's patch) with my AWE 32 card, > > which I had good results with before, and got like 5 to 8ms spikes. I'm > > not sure what the heck is going on with my machine now, but its > > certainly not good. > > I feel that your old results were too good. > But the new results seem also too bad compared with mine. > Or any hardware changes? hdparm, APM, etc.. >
I've been suspicious of that myself (the part about my old results being too good). Of course the sound output never had a glitch, whereas now I hear them sometimes (and the output is fairly fuzzed up, how would I send the audio stream with ALSA to a file? I've seen it on the list before, perhaps I would search the archives if geocrawler searched!). Of course I can't be sure how big the audio buffers were as there were some issues with oss emulation under ALSA with latencytest. > > Are there any programs that report what piece of > > code is causing big spikes? I haven't tested the 2.4.10 kernel yet, and > > if I did it would be bare without any patches (as I don't know of any up > > to date with 2.4.10). I did realize that the 2.4.9 kernel with LL patch > > is worse than the 2.4.5 one I was using. This might be because I > > compiled it with Mandrake's gcc a la 2.96. > > As far as I've experienced, the VM of 2.4.9 tends to have higher > latency under heavy disk loads. On 2.4.10 the VM was changed much and > became better. > > I discussed with Andrea about this problem, and he will check the > relevant part. Hopefully any patch will come to 2.4.11. > Sounds good. I noticed the memory management got worked heavily between 2.4.9 and 2.4.10. I couldn't really just logically do a manual apply of rejects for the LL patch for 2.4.9. Its nice to hear that its for the better :) > > > > By the way I'm posting my results to http://www.c0nfusion.org/~josh/ if > > you want to have a look. The only hardware that has changed in my > > machine since my previous tests (http://www.resonance.org/~josh/) is I > > added an SB Live!. I think I upgraded to Mandrake 8 between then, so > > most of the software is probably different. > > Ah, the last test looks really fantastic.. > I wish in near future we get it back! > Alas, the last test is with OSS (my test #4 was with ALSA though, which has similar #s as far as latency). I wonder about the OSS latencytest though. It seems like the latency is fairly equivelant. The only difference being the huge # of overruns with ALSA compared to OSS. I wonder if the OSS overrun detection is correct. I haven't looked at the latencytest code recently, but I seem to remember it manually determining if an overrun was caused or not (by comparing the latency with the fragment period). I also noticed that the buffer size with OSS was 1024 rather than 768 bytes. I think this is just one extra fragment though, so that shouldn't affect it right? > > ciao, > > Takashi Not sure if you saw my question about whether there is some way to determine where in the kernel a hold up occurs. How does Andrew Morton check those things? Seems like a tool to determine what driver, program or kernel routine is causing latency spikes would be a useful tool. -- Josh Green Smurf Sound Font Editor (http://smurf.sourceforge.net) _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
