[Intel-wired-lan] Kernel 4.6.7-rt13: Intel Ethernet driver igb causes huge latencies in cyclictest

Richard Cochran richardcochran at gmail.com
Mon Oct 17 19:03:34 UTC 2016


On Mon, Oct 17, 2016 at 01:36:45PM -0500, Julia Cartwright wrote:
> While that is certainly the case, and would explain the most egregious
> of measured latency spikes, it doesn't invalidate the test if you
> consider the valuable data point(s) to be the minimum and/or median
> latencies.

Well, consider the case where an interrupt is stuck on.  That is a
possible cause, and it can be positively excluded by either disabling
local interrupts around the time stamps or by putting the vector
events into the trace.

(Doesn't matter now that bisection fingered the PCIe setup, just sayin.)

Thanks,
Richard


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