[Haskell-beginners] reproducing HashTable benchmark

Tom Doris tomdoris at gmail.com
Sun Oct 10 07:01:59 EDT 2010


I've been investigating the performance of some word frequency counting code
I wrote, and I came across this stackoverflow thread
http://stackoverflow.com/questions/3058529/curious-about-the-hashtable-problemwhere
Dons shows simple benchmarks for HashTable and IntMap, but I can't
reproduce the "after the fix" performance of the HashTable code, I am very
confused as to what version of ghc actually has the fix.

In the post Don writes "With GHC 6.10.2, before the fix, inserting 10M
ints:" and then "With GHC 6.13, after the fix:", is this a typo, shouldn't
it read 6.10.3? Since there is no 6.13 version of ghc yet? If it should be
6.10.3, and I'm running v 6.12.1, why does the HashTable code in Don's post
take 22 seconds to run on my machine (compiled ghc --make -O2) and the
IntMap version takes only 5.8s? How can one find out what release the fix
for ticket #650 was released into? I've tried the release notes but I can't
seem to spot it, and google doesn't either. The ticket has "Milestone:
6.12.2" but that is struck-through, though the comments would suggest this
made it into r 6.12.2, I can't spot anything in the release notes for that
version either.

Can someone help clarify which version the fix will be/is in and how one
should figure this out in general for other issues?

Thanks
Tom
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