Performance regression 7.0.1 -> 7.0.1.20110201
Submitted by Kazu Yamamoto on glasgow-haskell-users.
This program
import System.IO
n :: Int
n = 10000
main :: IO ()
main = withFile "/dev/null" WriteMode $ \h ->
hPutStr h . foldr1 (++) . replicate n . replicate n $ 'a'
runs much more slowly with the current 7.0 branch than with either 7.0.1 or HEAD.
He also reported that the program runs faster interpreted with runghc than when compiled. I think this is due to #917 (full-laziness), so that's a separate issue. THe regression reported in this ticket is in compiled performance relative to 7.0.1 and HEAD.
I don't see any obvious differences in the simplified output, so the difference could be in library code. I'm using libraries compiled with -O2 in all cases.
Trac metadata
Trac field | Value |
---|---|
Version | 7.0.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | highest |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |