[alsa-devel] HDA irq understanding
Hi, I know my question is quite easy for this ml, but I hope to get a little help. I'm an embedded developer and I'm not so good with x86. I'm trying to load the system and hear mp3 decoding getting worst, but no way on my "Intel(R) Core(TM)2 Duo CPU P8400 @ 2.26GHz" very basic system. I'm trying to understand why I can't. Using trace (the complete one is here www.opensurf.it/trace12-02-04-19-14-48.txt_orig.lzma ) I get:
grep HDA trace12-02-04-19-14-48.txt .. cpu-100.sh-26486 [000] 9490.976257: irq_handler_entry: irq=21 handler=HDA Intel cpu-100.sh-26474 [000] 9490.984236: irq_handler_entry: irq=21 handler=HDA Intel cpu-100.sh-26467 [000] 9490.992220: irq_handler_entry: irq=21 handler=HDA Intel cpu-100.sh-26502 [000] 9491.088042: irq_handler_entry: irq=21 handler=HDA Intel .. almost every 10msec pulseaudio reads from /dev/snd/pcmC0D0p, mplayer reads from pulseaudio.
How can I create context switch problem in this situation and trace is well ? Thanks, Raffaele
--------------------- Loading the system --------------------- where I have lauched cpu-100.sh 20 times $ cat cpu-100.sh #!/bin/bash while : ; do true done
I have also launched root $ ping -l 100000 -q -s 10 -f localhost & once
--- www.opensurf.it
On 02/06/2012 08:06 AM, Raffaele Recalcati wrote:
Hi, I know my question is quite easy for this ml, but I hope to get a little help. I'm an embedded developer and I'm not so good with x86. I'm trying to load the system and hear mp3 decoding getting worst, but no way on my "Intel(R) Core(TM)2 Duo CPU P8400 @ 2.26GHz" very basic system. I'm trying to understand why I can't. Using trace (the complete one is here www.opensurf.it/trace12-02-04-19-14-48.txt_orig.lzma ) I get:
grep HDA trace12-02-04-19-14-48.txt .. cpu-100.sh-26486 [000] 9490.976257: irq_handler_entry: irq=21 handler=HDA Intel cpu-100.sh-26474 [000] 9490.984236: irq_handler_entry: irq=21 handler=HDA Intel cpu-100.sh-26467 [000] 9490.992220: irq_handler_entry: irq=21 handler=HDA Intel cpu-100.sh-26502 [000] 9491.088042: irq_handler_entry: irq=21 handler=HDA Intel .. almost every 10msec pulseaudio reads from /dev/snd/pcmC0D0p, mplayer reads from pulseaudio.
How can I create context switch problem in this situation and trace is well ? Thanks, Raffaele
Sorry, is your problem that you *do* get broken audio when you load the system, or that you *don't* get broken audio when you load the system?
Either way, PulseAudio uses RT prio to get higher priority than your load scripts, so this is used in PulseAudio <=> ALSA communication, but not in mplayer <=> PulseAudio communication.
For the 10 msec frequency, it looks like timer-based scheduling is turned off (or possibly mplayer is using very small buffer sizes?). You might get help with this in the pulseaudio-discuss mailinglist.
Hi,
Sorry, is your problem that you *do* get broken audio when you load the system, or that you *don't* get broken audio when you load the system?
I don't
Either way, PulseAudio uses RT prio to get higher priority than your load scripts, so this is used in PulseAudio <=> ALSA communication, but not in mplayer <=> PulseAudio communication.
In fact the first problems appears in gnome interface I'll do some SCHED_RR cpu loads applications.
For the 10 msec frequency, it looks like timer-based scheduling is turned off (or possibly mplayer is using very small buffer sizes?). You might get help with this in the pulseaudio-discuss mailinglist.
-- David Henningsson, Canonical Ltd. http://launchpad.net/~diwic
I'll do some test changing mplayer buffer.
Thx,
participants (2)
-
David Henningsson -
Raffaele Recalcati