Hi,

I need high precision timer which returns the accurate value
till 99.99 percentile. I am using clock_gettime(MONOTONIC_RAW,..)
in a tight loop and measuring the timing difference between consecutive calls.

For 99.8 percentile I see timediff of 100 nano sec but then there are few values(5 out of 10000 calls) which are in millisec. At this moment I am clueless what may be the reason behind it.

I am using linux debian kernel 2.6.28, with core scheduling on core 0. The timing measurement are done with program tied to the other core. I have also disabled ntp.

Any possible explanation what may be the reason for such measurement
outliers?


Thanks !