Strange pauses and cpu usage - FreeBSD 6.1

Shawn shawnh at f2s.com
Sun May 28 05:27:20 PDT 2006


On Sun, 28 May 2006 01:02:35 -0400
Kris Kennaway <kris at obsecurity.org> wrote:

> On Sun, May 28, 2006 at 02:18:36AM +0200, Xavier Chantry wrote:
> > On Sat, May 27, 2006 at 01:14:13AM +0100, Shawn wrote:
> > > I'm having a strange problem with cpu usage with my Athlon XP.
> > > Every so often there seems to be a pause where the system comes
> > > under heavy load for no apparent reason. If xmms was playing then
> > > I get a buzz sound and the mouse pointer stops just for a split
> > > second, the same with mplayer and vlc. Using Opera or firefox
> > > also seems to have a strange effect where the mouse pointer
> > > freezes while pages load, and if there is an animated gif on the
> > > page the cpu usage goes to 100%.
> > > 
> > > The jabber client Gajim also makes the cpu get stuck at 100%.
> > > When I used gnome, nautilus did the same thing until i stopped
> > > and started the process in the system monitor. I have searched
> > > around and found this tip from the handbook but it had no effect.
> > > 
> > > hint.apic.0.disabled="1" in /boot/loader.conf
> > > 
> > > This happens with the generic kernel and the one i compiled for
> > > myself. It also lasts for a random amount of time, sometimes it
> > > is barely noticeable and sometimes it happens for over a second.
> > > Running neverwinter nights makes the system pause for 10-20
> > > seconds seemingly randomly.
> > > 
> > 
> > My system behaves much better than that, I've no mouse freeze and no
> > system pauses, but I did have occasonial sound skips using 4bsd on
> > 6.1. Switching to the ULE scheduler seems to fix this problem, but
> > other things may behave worse.
> > One year ago, it was actually the opposite, sound in ULE was really
> > jerky, and mouse pointer too while eg launching an app.
> > Did you already try both schedulers ?
> 
> Check for interrupt sharing with vmstat -i.  Shared interrupts cause
> performance loss especially if it's sharing with a giant-locked driver
> like USB.
> 
> Kris

I tried switching to ULE and while the sound skipping seems to have
stopped, the other problems remain.

vmstat -i gives me:

interrupt                          total       rate
irq0: clk                          69873        984
irq7: ppc0                             2          0
irq8: rtc                           8944        125
irq10: atapci0++                    2409         33
irq11: nvidia0++                    5264         74
irq12: pcm0 rl0+                      41          0
irq15: ata1                           47          0
Total                              86580       1219

So it seems that net and sound are sharing irq12, and just before i
see the freeBSD bootloader i can see that irq12 is used for the usb
controller. Is this my problem? I have no irq settings in the
BIOS and i tried a device hint for pcm to move it up to irq13 but had no
luck.

Forgive me if I am missing something obvious somewhere along the line,
I only started using freeBSD a few weeks ago and I am totally new to
BSD in general.

Thanks for the help!

~shawn


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