On Tue, Jun 27, 2006 at 07:32:04AM -0700, Stephane Eranian wrote: ... > > 5006 hardware interrupts in 10 seconds, 16359 interrupt-disable events ==> > > the kernel disabled interrupts 11353 times for critical sections. To get > > useful results it looks like booting with idle=poll and disabling cpufreq > > is needed, though, since interrupts_masked_cycles (non-edge mode) counts > > even when the CPU is halted: > > Yes, I think you need to be careful with the idle thread, some events may or > may not count when going low-power. I think it is best to avoid going > low-power for measurements. Any benchmarking that involves IA64 idle thread is strongly reccomended to use "nohalt" option. It's about a 15-20% performance difference on some interrupt intensive benchmarks (e.g. netperf TCP_RR). If someone has measured the delta for other architectures that go into a "low power" state in idle thread, I'd be grateful if they posted the results or mailed them to me. thanks, grant - : send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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