Re: [boost] very poor thread performance

From: James Sutherland (James.Sutherland_at_[hidden])
Date: 2008-05-14 17:27:01

>
>> Okay, then I am interpreting things correctly, and my internal timer
>> seems to be consistent with the output of the "time" command that you
>> refer to.  To restate, the sum of "real" and "system" time is the
>> pertinent measure.  The results you posted then indicate that there  
>> is
>> no speedup associated with increasing the number of threads.  I am  
>> now
>> seeing the same thing...
>
> No, the "real" time is the pertinent measure.  I'm saying the  
> program took
> 4.991s to complete with 2 threads and 9.668s to complete with 1  
> thread.  You
> might be less confused if you increase the number of loops in  
> operator() so
> the program is slow enough you can measure the execution time by  
> watching a
> clock.
>

Frank,

Thank you for your patience with me.  I am now understanding this  
correctly.  I did not realize that the clock() function would double- 
count in multithreaded applications.

I took your suggestion of increasing the loop count and that clarified  
it for me.  It appears that I do have scalability after all...

James