Messages in this thread | | | Date | Wed, 28 Feb 2018 12:50:48 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: HRTimer causing rtctest to fail |
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On Wed, 28 Feb 2018, Felipe Balbi wrote: > Thomas Gleixner <tglx@linutronix.de> writes: > > All numbers in micro seconds! What happens if you load the system or > > restrict C-States? > > added intel_idle.max_cstate=0 to cmdline. Still see some failures, > albeit a lot more rare, for example, caught one on iteration 8 of > 8192Hz: > > 8192Hz: 1 2 3 4 5 6 7 > PIE delta error: 0.000135 should be close to 0.000122 > > That is, however, only 13 uS late. Is that within the limits of "we > don't quite care"?
I think so. 13us (depending on the machine) can easily happen if multiple interrupts/timers happen at the same time or if something keeps interrupts disabled for a few microseconds which is certainly possible.
What kind of system is this?
> BTW, it took some effort to get that one failure. I'll leave rtctest > running in a long loop and try to figure out approximately how frequently > it fails, but it seems like it's within the realm of "don't care", would > you agree?
Yes.
Thanks,
tglx
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