Re: [jamboost] Profiling output inaccuracy

From: Vladimir Prus (ghost_at_[hidden])
Date: 2002-07-22 11:50:00

David Abrahams wrote:
> From: "Vladimir Prus" <ghost_at_[hidden]>
>
> > Say you call x which call x which calls x. I'll refer to function
>
> instances as
>
> > x1, x2 and x3 ;
> >
> > Cumulative time for x will include
> > net time for x3 +
> > net time for x2 + total time for x3 +
> > net time for x1 + total time for x2
> > and this is equal to
> > net time for x1 + 2 * net time for x2 + 3 * net time for x3.
> >
> > You're counting the same time several times!
>
> Hmm, no wonder recursive calls appeared to be so expensive!

Well... that's why my previous message used calls to 'hashitem' to compare 
performance.

> It seems like a simple fix is possible - put an entry count on profile_info
> and only accumulate cumulative time when it goes to zero.

Yea, guess that will work. Comitted the change -- oh... now the profiling 
information looks much more reasonable -- as expected, class.__init__ is 
responsible for the largest fraction of classes overhead.

- Volodya