Hi Alain,

    I think what you're seeing here is clock resolution.  I think you're
running too simple a benchmark to get reliable results.  When I run on Cog
(2.66GHz Intel Core i7) I get most results around 65,000,000, the occasional
one around 50,000,000 and rarely one around 98,000,000.  But when I try
evaluating 30 benchFib instead of 26 benchFib things settle down.  When I
use 32 benchFib (which takes around 125 ms) I see very small variance, every
result being between 55,000,000 and 58,000,000.  SI experiment with
different values and see if your times settle down as you increase N also.

On Fri, May 21, 2010 at 2:37 PM, Alain_Rastoul <alr.dev at free.fr> wrote:

> Right, it has nothing to do with commonSend and cache.
> Being stubborn I added cache hit / misses counters to the vm but it showed
> nothing significant except a very good ratio : 95 to 98%  :)
>
> In addition, putting the squeak process to a lowest priority (even "idle")
> seems to make it run much faster (!!!).
> Strange Windows.
>
> Regards
>
> Alain
>
> "Levente Uzonyi" <leves at elte.hu> a écrit dans le message de news:
> Pine.LNX.4.64.1005211945090.15643 at login01.caesar.elte.hu...
> > On Fri, 21 May 2010, Alain_Rastoul wrote:
> >
> >> Hello,
> >>
> >> I recently tryed then 4.1 and discovered a strange behavior that
> >> appearead
> >> to be true with the 3.10 also.
> >> The test is simply running benchFib in series of runs.
> >> If I run the test 10 times, on of the run is about 2-3 times faster than
> >> the
> >> others, and I can't explain that.
> >>
> >> 10 timesRepeat: [
> >> | r t |
> >>   t := Time millisecondsToRun: [r := 26 benchFib].
> >>   Transcript show: ((r * 1000) // t) ; cr.
> >> ]
> >
> > I can't reproduce this. I think it's just noise from your OS. But try to
> > evaluate this:
> >
> > [
> >  ((1 to: 100)
> >  collect: [ :run |
> >  (Integer >> #benchFib) flushCache.
> >  [ 26 benchFib ] timeToRunWithoutGC ]) sort ] valueAt: 80.
> >
> > If you get the same results, then GC and caching doesn't change the
> > behavior, so you can be pretty sure that it's just OS-noise. Try
> > increasing the priority of Squeak's process and repeat the tests.
> >
> >
> > Levente
> >
> >>
> >> will give me 10 numbers about 2486297 (one of the runs)
> >> but one run will give me 10 numbers about 6773017.
> >> I stopped all I could stop on my laptop and nothing else but squeak is
> >> running...
> >> I made a TimeProfileBrowser and the inner loop of the profile seems to
> >> show
> >> that primitives are more than 2 times faster.
> >> (and everything seems 2 times faster)
> >> Anybody noticed that (I searched the web but found nothing) ?
> >> primitive calls ?
> >> methodCache?
> >>
> >>
> >> Best regards,
> >>
> >> Alain
> >>
> >>
> >>
> >>
> >>
> >
> >
>
>
>
>
>
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