Paul Hartman <paul.hartman+gen...@gmail.com> posted 58965d8a0906170914l4ebca650uba703a2a6b450...@mail.gmail.com, excerpted below, on Wed, 17 Jun 2009 11:14:50 -0500:
> Well, if you want something different then KDE4 is definitely > different... for better or for worse :) Agreed, but if he wants low latency, he'll probably want to be sure to turn off all the fancy 3D window effects, transparency and the like, and with that goes much of the reason for using KDE4. =:^( If he has a fast graphics card and a relatively low resolution screen, he may be able to get away with very limited effects, but if I'm right, even that might be a bit too unpredictable in terms of latency. Meanwhile, Mark, you do have the kernel set for a 1000 Hz clock rate, right? And you have preemptive desktop turned on, and high resolution timers, right? (These are under Processor type and features.) You may also wish to experiment with Group CPU Scheduler (under General setup), if you regularly run background tasks as other users and you want to be sure your audio user gets his share of CPU. With that on you can then tweak the /sys/kernel/uids/<idnum>/cpu_share numbers, keeping in mind that the default is 1024 while the root default is 2048, and that the <idnum> dirs will come and go as users do. I don't do your sort of audio, and run the more moderate voluntary preemption and 300 Hz clock (with tickless also on), but combined with setting PORTAGE_NICENESS=19 in make.conf, I can run all sorts of emerge jobs, CPU loads in the hundreds if I want as long as don't run too far into swap, and still keep a relatively responsive desktop, and if I had full preemption and 1000 Hz, I think I could almost do your style of recording even while running emerges! (Oh, I also have PORTAGE_TMPDIR pointed at a tmpfs, thus keeping unnecessary I/O to a minimum. That makes a difference to responsiveness while merging too, as does having the memory to keep it out of swap while doing so.) Of course, it may be that you simply don't run enough background tasks as other users to make any difference with the group scheduling stuff, and that was only added in 2.6.27 or some such, so if you're running an old kernel you won't have the group scheduling at all. IOW, YMMV, but it's worth looking at. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman
