Messages in this thread | | | From | "Peter T. Breuer" <> | Subject | Re: Interesting scheduling times - NOT | Date | Wed, 23 Sep 1998 14:59:29 +0200 (MET DST) |
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"A month of sundays ago Richard Gooch wrote:" > > As I've already said, you're probably not seeing the variance because > you don't run with RT priority. If I run my test with SCHED_OTHER then
Naively (and that's my chief virtue :-) I see
a) Larry's tests show 100% variance between _different_ runs, each run with different numbers of background processes.
b) Richard's tests show 100% variance during _one_ test run, and he sees unpredicatbly varying numbers of processes on the run queue during the run. Variance drops when he tries to stabilize those numbers.
and I would venture to suggest that's about 70% of the cause. I.e. a hidden variable. I'd like to see the full spectra of results and do my own stats on it. Why are you all bleating about min/median when you have the full distribution available? I don't know the dist of a min offhand, but it strikes me as being intrinsically highly variable on a normal dist.
Peter
> It was not uncommon to start the benchmark with 2 processes on the run > queue and finish with 10. > With the settling-down delay, I'm now finishing the benchmark with 2 > or 3 processes on the run queue (rarely 4). > This has made the variance in the median come down to 10% in the case
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