* [9fans] very high interrupt rates
@ 2011-08-25 9:59 Steve Simon
2011-08-25 13:27 ` erik quanstrom
0 siblings, 1 reply; 2+ messages in thread
From: Steve Simon @ 2011-08-25 9:59 UTC (permalink / raw)
To: 9fans
Hi,
This is not a critical problem, more a point of interest.
My new desktop machine reports very high interrupt rates in stats,
the bargraph on stats is stock at 100%, a count of 176000 (ints/sec ?)
I added erik's interrupt counter code and see that these are occuring
on irq 10, which my hardware ties to the SATA interface and usbuhci
(a combined Intel 82801EB/ER chipset).
the other difference between this system and my previous one is
I now have a USB keyboard and mouse (rather than PS2).
Is there a problem with my USB or is it a case of "they all do that"?
-Steve
-----------------
larch% grep '10|clock' /dev/irqalloc
50 18 1196593585 clock
105 10 167041275929 sdF (ata)
105 10 167041275930 sdE (ata)
105 10 167041275932 usbuhci
# whyirq below prints the difference in /dev/irqalloc over a 4 second period.
larch% whyirq
trap irq count rate name
73 11 136 34.00 ether0
65 1 1 0.25 kbd
105 10 601952 150488.00 usbuhci
50 18 4340 1085.00 clock
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [9fans] very high interrupt rates
2011-08-25 9:59 [9fans] very high interrupt rates Steve Simon
@ 2011-08-25 13:27 ` erik quanstrom
0 siblings, 0 replies; 2+ messages in thread
From: erik quanstrom @ 2011-08-25 13:27 UTC (permalink / raw)
To: 9fans
> My new desktop machine reports very high interrupt rates in stats,
> the bargraph on stats is stock at 100%, a count of 176000 (ints/sec ?)
>
> I added erik's interrupt counter code and see that these are occuring
> on irq 10, which my hardware ties to the SATA interface and usbuhci
> (a combined Intel 82801EB/ER chipset).
>
> the other difference between this system and my previous one is
> I now have a USB keyboard and mouse (rather than PS2).
>
> Is there a problem with my USB or is it a case of "they all do that"?
>
> -Steve
>
> -----------------
> larch% grep '10|clock' /dev/irqalloc
> 50 18 1196593585 clock
> 105 10 167041275929 sdF (ata)
> 105 10 167041275930 sdE (ata)
> 105 10 167041275932 usbuhci
if you're using the standard HZ of 100, then your machine
has been up ~138/nmach days? if that's correct, then nevermind.
otherwise, is it possible that you are counting cycles and not
interrupts?
in any event, if you use a 9atom kernel, you may be able to
get the ata drives on a different vectors (assuming they support msi)
and then you could tell more precicely what's going on.
sadly usb is incompatable with msi; broken by design.
as a wild guess, i think you could fix your problem either by
using the 9atom ide driver or telling the motherboard to
present the drives as ahci.
- erik
p.s the format i've been using for irqalloc on 386 has been
Reads from irqalloc return the enabled interrupts, one line
per interrupt. Each line contains three fields separated by
white space: the trap [sic] number, the IRQ it is assigned to, and
the name of the device using it.
minooka; cat /dev/irqalloc
3 0 0 0 trap debugpt
7 0 0 0 trap mathemu
8 0 0 0 trap doublefault
9 0 0 0 trap mathover
14 0 0 0 trap fault386
15 0 0 0 trap unexpected
16 0 0 0 trap matherror
50 18 9052758077 20828942019320 lapic clock
51 19 0 0 lapic lapicerror
63 31 0 0 lapic lapicspurious
65 1 6 4231380 ioapic kbd
73 15 76377411 457040194416 msi ether0
81 15 520404 4488965428 msi ether1
89 5 0 0 msi ether2
97 4 408 7531904 ioapic COM1
105 11 3 51732 msi sdE (ahci)
see http://www.quanstro.net/magic/man2html/3/arch
^ permalink raw reply [flat|nested] 2+ messages in thread
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2011-08-25 9:59 [9fans] very high interrupt rates Steve Simon
2011-08-25 13:27 ` erik quanstrom
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