yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

I can confirm that yade is about 30% faster when profiling is disabled, 
and that callgring still give similar results (except that it is a lot 
more readable since you don't have to mentaly remove time spent in 
mcount). No debug symbols needed either.

Bruno



Bruno Chareyre a écrit :
> I just ran a profiling job, and I have a questionning result.
>
> 45% of cpu time is used for the function "mcount" from libc.
>
> According to some googling :
>
> "gcc inserts calls to mcount() at the start and end of functions if 
> profiling (-p) is enabled."
>
> That is good, it seems this operation will not take time if profiling 
> is disabled (and it takes so much time because of function calls like 
> "iterator++" or "body::byId(i)").
>
> But then I have two questions in mind :
> 1. How comes valgrind/kcachegrind is not removing the time for mcount 
> from results? It would make sense.
> 2. Why could I profile for years without option -p and I could get 
> (apparently) consistent results?
>
> Just asking in case somebody knows the answer already.
>
> Bruno


--

_______________
Chareyre Bruno
Maitre de conference

Grenoble INP
Laboratoire 3SR - bureau E145
BP 53 - 38041, Grenoble cedex 9 - France
Tél : 33 4 56 52 86 21
Fax : 33 4 76 82 70 43
________________