#3655: Performance regression relative to 6.10
---------------------------------------+------------------------------------
Reporter: simonmar | Owner:
Type: run-time performance bug | Status: new
Priority: high | Milestone: 6.12.2
Component: Compiler | Version: 6.10.4
Severity: normal | Keywords:
Difficulty: Unknown | Testcase:
Os: Unknown/Multiple | Architecture: Unknown/Multiple
---------------------------------------+------------------------------------
The attached program runs more slowly when compiled with 6.12 compared to
6.10. The current HEAD is also worse than 6.10, but not as bad as 6.12.
The results are below, on x86-64/Linux, first with -O:
{{{
time allocation
6.10.2 9.6s 6.5GB
6.12.20091011 11.0s 7.5GB
6.13.20091111 10.2s 6.2GB
}}}
Interestingly, `-O2` makes things even worse with 6.12, but makes things
slightly better with both 6.10 and 6.13:
{{{
time allocation
6.10.2 9.5s 6.5GB
6.12.20091011 11.8s 7.5GB
6.13.20091111 10.1s 6.2GB
}}}
It may be that there is some degradation due to the new IO library, since
the program generates a fair amount of output. That may account for some
of the difference between 6.10.2 and 6.12/6.13, but it doesn't account for
the difference between 6.12 and 6.13, which are both using the new IO
library.
The program is in one module, compile with no special options. To run it:
{{{
./pHlcm mushroom.dat 100 >/dev/null +RTS -s
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3655>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler_______________________________________________
Glasgow-haskell-bugs mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
