Re: [boost] [compute] Review

Subject: Re: [boost] [compute] Review
From: John Bytheway (jbytheway+boost_at_[hidden])
Date: 2014-12-30 23:33:24

On 2014-12-29 02:01, Kyle Lutz wrote:
> On Sun, Dec 28, 2014 at 7:26 PM, John Bytheway
> <jbytheway+boost_at_[hidden]> wrote:
>> - It looks like the performance tests don't include the time for copying
>> data to (and, where applicable, from) the device.  You should mention
>> this on the Performance page.
> 
> I'll add this, though it is very device/system specific. Also, there
> is a performance benchmark available in Boost.Compute
> ("perf_copy_to_device") which could be used to measure this on your
> own system.

More on the subject of performance:

I ran some of the performance tests on my machine, and I observed
something surprising.

set_intersection and set_difference are *unbelievably* fast (two orders
of magnitude faster than the std:: versions), and yet set_union and
set_symmetric_difference are quite slow (maybe twice as slow as std::).
 Looking at the code, the four algorithms are very similar.  Have you
any idea what causes this huge discrepancy in their speed?

John