Hi folks.
OK, try this:
darcs get http://darcs.orphi.me.uk/MyMD5
cd MyMD5
ghc -O2 --make md5sum
md5sum <some large filename>
On my PC, it takes 3.5 seconds to compute the MD5 hash of a 10 MB file.
For comparison, the md5.exe I downloaded from the Internet does it
instantaneously. It's literally so fast I can't even time it. As far as
I know, my program always produces the *correct* answer, it just takes
far too long to do it.
If anybody has any interesting insights as to why my version is so
damned slow, I'd like to hear them. (Indeed, a description of the
process for tracking the problem down would also be useful!)
[Much to my bemusement, when I had a look at the code, I discovered that
tucked away in a corner somewhere, it reads a ByteString from disk and
instantly converts it to [Word8]. Uh... oops? Anyway, eliminating this
changed the numbers I get from the profiler, but it's still far too slow.]
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