Re: Few interrupts with NO_HZ

From: Chris Snook
Date: Mon Aug 06 2007 - 09:48:23 EST


Jan Engelhardt wrote:
Hi,


this more of an informational question. So:

kernel version is 2.6.22.1 on i686

/proc/uptime 9917.81 9140.90 (2h45m)

/proc/cpuinfo:
CPU0
0: 282 IO-APIC-edge timer

this is kinda neat, I expected much more interrupts than just 282 since boot. What kernel code actually uses the irq0 timer?

If you don't have an HPET (and most single-processor systems do not) the kernel is probably using the PIT to wake the processor from low-power sleep states, since the LAPIC timer is disabled in these states. If your box is mostly idle, you might want to use powertop to figure out why it's entering low power states so infrequently.

-- Chris
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