On Mon, Jun 13, 2011 at 05:38:11PM -0700, Fernando Lopez-Lezcano wrote: > Hi all, > > I just built a threaded-irqs enabled 2.6.39.1 kernel and used > cyclictest to try to get an initial feeling of how good it might be. > Cyclictest tests scheduling delays of the kernel it is running > on[*]. These tests were run on a Fedora 13 T510 Lenovo laptop, with > the ugly binary Nvidia driver (caveat emptor). > > In the menu: > > 2.6.39.1 with threaded irqs and PREEMPT active > 2.6.33.13-rt31 > 2.6.34.8-rt31 (a forward port of rt31 to 2.6.34) > plain Fedora kernel (2.6.34.8-68.fc13.i686.PAE) > > Now, before someone points it out, this is just a synthetic test > that measures scheduling latency, not a real audio application. still... it provides some numbers. and what i get seems to differ from what you get pretty heavily. ---( torbenh@siel )---( ~/cvs/rt-tests )--- -> uname -a Linux siel 2.6.39 #53 SMP PREEMPT Wed May 25 22:11:00 CEST 2011 x86_64 GNU/Linux ---( torbenh@siel )---( ~/cvs/rt-tests )--- -> ./cyclictest -t1 -p 80 -n -i 10000 -l 10000 -m policy: fifo: loadavg: 2.34 1.27 0.54 5/267 10411 T: 0 ( 7904) P:80 I:10000 C: 10000 Min: 8 Act: 19 Avg: 17 Max: 97 ---( torbenh@siel )---( ~/cvs/rt-tests )--- its just a single run. with a kernel compile in the background. and thats WITHOUT threadirqs > See below for details... (look at the "Avg:" and "Max:" latency > values, those are in microseconds) > > Unless I have done something wrong, it looks like we have a long way > to go with regards to scheduling latency in anything other than > 2.6.33 + rt patches. But, with threaded irqs in 2.6.39 maybe the > performance with audio applications running under jack will be good > anyway as we will be able to tune irq processing. Seems to me > unlikely. I have not tested that yet. you did not use -m ... although that didnt really change much for me. but i have plenty of RAM here. > > Tests were done after a clean reboot, initially with the machine > idle and then while loading thunderbird with tons of emails and > firefox with tons of pages. No audio work. hmm... maybe i should have loaded up ff... but i loaded midori. because ff was already running. > > YMMV... > -- Fernando > > [*] https://rt.wiki.kernel.org/index.php/RT_PREEMPT_HOWTO > > > ---------------------------------------------------------------------- > LENOVO T510 > -- torben Hohn _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
