GHC-6.4.1 much slower than GHC-6.4
rahn at ira.uka.de
Thu Oct 27 11:47:19 EDT 2005
I was surprised about really big differences in running times between
6.4 and 6.4.1, whereby 6.4.1 is *much* slower:
*** 6.4: cpu-time interesting (3,3): 00:01:38.08
*** 6.4.1: cpu-time interesting (3,3): 00:05:58.91
Here we have a factor of about 3.6!! Are there others that have noticed
such behavior? What could be the reason for that?
Sorry, my example is a small monster, but at the moment there is neither
time left to search for the reason for this behavior nor to break it
down to some smaller pieces of code. I just noticed it...
However, you can find the source tree in
contains the tree as well. For the output above: Extract, cd proj/prog
rahn at i90pc18:~/local/proj/prog$ for version in 6.4 6.4.1; do find .
-name '*.hi' | rm -f ; ghc-$version --make -Wall -cpp
-D__POS__='__FILE__ ++ "[" ++ show(__LINE__::Int) ++ "]: " ++ '
-fallow-undecidable-instances -O Prog/Interesting.hs -o
Prog/Interesting.$version.bin 2>/dev/null >/dev/null; echo -n "***
$version: " ; ./Prog/Interesting.$version.bin 2>&1 | grep time ; done
P.S.: I run a debian-box with i686 GNU/Linux 220.127.116.11 and a dualcore P4
-- Mirko Rahn -- Tel +49-721 608 7504 --
--- http://liinwww.ira.uka.de/~rahn/ ---
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