Re: top displaying 50% si time and 50% idle on idle machine

From: Metathronius Galabant
Date: Mon Sep 11 2006 - 07:47:39 EST


>>>>Cpu(s): 0.0% us, 0.0% sy, 0.0% ni, 50.0% id, 0.0%
>>>>wa, 0.0% hi, 50.0%si

>> BTW what means si? (interrupt service time? google
>> didn't find anything)

> 'soft interrupt' probably. try disconnecting network.

The cause has been found. The timer of that machine is seriously
broken, 1 second is approximately 500ms long.
It is a HP DL360 G4 and I configured the kernel without ACPI or
similar. Maybe there are some strange BIOS power management schemes
active. I will look deeper into the problem and report back.
A broken timer is _very_ strange to me (I didn't encounter that in the
last 12 years w/ custom kernels).

Power management was completely switched off, so that was not the cause.
Instead, please have a look the this dmesg outputs:

not working (no ACPI):

ENABLING IO-APIC IRQs
unknown bus type 32. (repeated MULTIPLE TIMES!)
..TIMER: vector=0x31 apic1=-1 pin1=-1 apic2=-1 pin2=-1
...trying to set up timer (IRQ0) through the 8259A ... failed.
...trying to set up timer as Virtual Wire IRQ... works.


working (ACPI + processor support):

ENABLING IO-APIC IRQs
..TIMER: vector=0x31 apic1=0 pin1=2 apic2=-1 pin2=-1

Can this be considered as a kernel-bug?

Thanks for the help,
M.
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