Messages in this thread | | | Date | Mon, 06 Aug 2007 10:35:30 -0400 | From | Chris Snook <> | Subject | Re: Few interrupts with NO_HZ |
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Jan Engelhardt wrote: > On Aug 6 2007 09:47, Chris Snook wrote: >>> 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) > > This is an AMD Athlon with 'Thoroughbred' core; it does not seem to > have C-states at all (or: exactly one). It clearly is not idle all the > time, sometimes I run povray. (And 282 has not changed since the > morning.) > > > Jan
In that case, it's probably the early bootstrap code that runs before the TSC is calibrated. PIT sucks, but it sucks very reliably, so it's a good basis for calibrating the other timekeeping devices. Once you have something better set up, you don't need it anymore if you're not doing C-state transitions.
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