vmstat -i output after solving snd problems.

Marcin Koziej creep at desk.pl
Sun Oct 1 09:08:36 PDT 2006

I use FreeBSD STABLE on Acer Aspire 1525, with VIA K8M400 chipset and 
VIA1612A on-motherboard sound card.

I've beet tracing STABLE from some time ago, and at some point of 5.X 
series my sound started to be distorted (clicks, lags, metallic sounds) 
in a random manner, with distortions correlated with network/disk activity.
(This was reported before -- kern/81599, and some posts here and there)

After setting hint.pcm.0.buffersize to a bigger value and applying 
patches from 	http://people.freebsd.org/~ariff/  (BTW: contrary to the 
message there, these don't seem to be MFC'ed (?)) the sound distortions 
were completely simultaneous with network activity. Neither CPU load 
(and acpi_perf changing the cpu speed) nor high disk i/o (unpacking 
sources, making /usr/libexec/locate.updatedb) affected the sound, but 
only as I entered IRC or openned some pages in a browser I did hear 
clicks and lags.
Apparently the reason was  pcm0 and re0 (Ethernet card) sharing one irq.

By setting a different IRQ for some of devices in BIOS and turning off 
APIC, I got a new irq layout which gives pcm0 an exclusive IRQ.
I rejoiced, because the sound is perfect now.

However, I have few questions:

1) Is turning off APIC a disadvantage? (I have read the wikipedia page 
on IO-APIC and I the machine is uniprocessor)
Will it bring my performance down? Or do other scary things to me?
Maybe there is a better way to force different IRQ layout.

2) vmstat -i now shows:
interrupt                          total       rate
irq0: clk                        6824889        968
irq1: atkbd0                       13103          1
irq4: sio0                             2          0
irq7: ppc0                            71          0
irq8: rtc                         890176        126
irq9: nvidia0 cbb*                464262         65
irq10: cbb0 uhci1*                     3          0
irq11: ndis0 re0+                 130633         18
irq12: psm0                       597273         84
irq14: ata0                       118892         16
irq15: ata1                           74          0
Total                            9039378       1283

Does it look normal? What do '*' and '+' after device names mean?
I couldn't find this information in man vmstat, google or even quich 
grep through vmstat.c. What am I missing?
Is there something to be worried about this?

Thank's for Your time and sorry for crossposting to -multimedia@ (some 
people searching it might (?) find this post helpful).



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