On Monday, 14 September 2015 at 14:40:29 UTC, H. S. Teoh wrote:
If performance is a problem, the first thing I'd recommend is to use a profiler to find out where the hotspots are. (More often than not, I have found that the hotspots are not where I expected them to be; sometimes a 1-line change to an unanticipated hotspot can result in a huge performance boost.)
I agree with you on that. I used Python's cProfile module to find the performance bottleneck in the Python version I posted, and shaved off 8-10 seconds of runtime on an extraneous str.split() I had missed. I tried using the built-in profiler in DMD on the D program but to no avail. I couldn't really make any sense of the output other than that were enormous amounts of calls to lots of functions I couldn't find a way to remove from the code. Here's a paste of the trace output from the version I posted in the original post: http://dpaste.com/1AXPK9P
The next thing I'd try is to use gdc instead of dmd. ;-) IME, code produced by `gdc -O3` is at least 20-30% faster than code produced by `dmd -O -inline`. Sometimes the difference can be up to 40-50%, depending on the kind of code you're compiling.
Yes, it really seems that gdc or ldc is the way to go.
