Re: Toy computational "benchmark" in Ada (new blog post)

[David Trudgett <dktrudgett@gmail.com>]

Il giorno venerdì 7 giugno 2019 14:50:07 UTC+10, Paul Rubin ha scritto:
> 
> C++ version results: single threaded 45.73 seconds cpu, 47.36 sec elapsed.
> Multi-threaded (4 threads): 84.34 sec cpu, 23.11 sec elapsed.

You have not coded the same thing as the Ada code. Do you know any Ada at all?

> 
> That's using GCC 6.03 with threading done by std::future's async
> function.  So both versions are a fair amount faster than the Ada
> version, but the threading speedup is nowhere near as good.  I wonder
> what's going on with that.  At each of the 50 calculation runs, I launch
> 4 threads 

As you should know, the Ada code does not do this.


> for slices of the array, then wait for them to complete and
> sum the results, so there might be a little bit of idle time if the
> threads don't all use the exact same amount of time.

While eye-balling the Ada test runs, it seems that each of the eight tasks take virtually identical times. I didn't bother outputting the individual run times, however.

> 
> I also want to try with transform_map_reduce and maybe the new Intel TBB
> library with GCC 9.  It is possible that transform_map_reduce can use
> Intel SIMD intrinsics but otherwise they can be called directly with
> some hassle.  Also I can run on a machine with AVX512.
> 
> I guess the next thing after that would be OpenCL or CUDA and a graphics
> card.

Good luck with that! :-)

Cheers,
David