On Friday, 16 March 2012 at 14:26:19 UTC, Andrei Alexandrescu
wrote:
On 3/16/12 8:39 AM, Jay Norwood wrote:
On Friday, 16 March 2012 at 13:20:39 UTC, Jay Norwood wrote:
btw, the u++ page claims in the link below to be faster than D
by 70% on
some operations, which they attribute to their STL rewrite.
Maybe
someone should take a look at what they've done. Or maybe this
comparison is out of date...
http://www.ultimatepp.org/www$uppweb$vsd$en-us.html
The test uses a specific data structure, an indexed contiguous
array. To conclude from here that C++ is faster than D is quite
a stretch.
Andrei
Ok, but maybe the the upp arrayMap is pretty efficient for
certain things ... by their benchmarks 4x faster than STL on
whatever they were doing. I tried rewriting the D example code,
and upp is consistently a bit faster when running on a single
core.
http://www.ultimatepp.org/src$Core$ArrayMap$en-us.html
A D std.parallelism library rewrite of the example runs about 2x
faster than the current upp example code on a corei7 box, if you
give it several files to work on. The execution doesn't scale as
much as I expected, probably because the dictionary gets
duplicated in the parallel case, while the single thread just
increments counts in the same dictionary.
I believe the TDPL book mentioned some research on non-locking,
shared memory containers, but I didn't see anything documented in
the D libraries. There is the workerLocalStorage area ... but it
wouldn't help with the problem of the dictionary getting
duplicated in this case. It look like there would be a reduce
step required to merge the dictionary counts at the end.
