Re: boost.timer

From: Gennadiy E. Rozental (rogeeff_at_[hidden])
Date: 2001-11-01 03:20:16

> 2)  On many systems, either the timer precision is so low or the 
time 
> latency is so high that it is impossible to use to measure the time 
spent 
> in a single function invocation, unless the function is a major 
time 
> burner.  The only reliable way is to invoke the function a very 
large 
> number of times, and then divide the elapsed time by the number of 
> invocations.  This problem isn't unique to boost::timer, and is 
probably 
> getting much worse a clock speeds increase.  How many modern 
platforms can 
> actually deliver timings with high enough precision and low enough 
latency 
> to accurately measure a single invocation of a smallish function?
> 
> I'm inclined to think the solution may not be to try to fix timer, 
but
> to specify a new timing library with much more precise semantics.
> 
> --Beman

I think it would be a real chalange to write a portable 
implementation for the function that for the given user function, 
timer facility and user hint for how long the function should work 
will calculate the real time the function work. It could need to 
calculate somehow how many times it should run the the user function 
for appropriate precision to be reached. Alsp effects of using timer 
should be messured. It's like in theoretical phisics: mesuring tools 
affect messured subject. I once read an articale with some solution - 
do not remember where (I think in C++ Report).

Gennadiy.