#6104: Regression: space leak in HEAD vs. 7.4
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Reporter: simonmar | Owner:
Type: bug | Status: new
Priority: highest | Milestone: 7.6.1
Component: Compiler | Version: 7.5
Keywords: | Os: Unknown/Multiple
Architecture: Unknown/Multiple | Failure: Compile-time performance bug
Difficulty: Unknown | Testcase:
Blockedby: | Blocking:
Related: |
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Comment(by simonmar):
I've narrowed this down to something that happened around May 8-10. I'm
seeing a roughly 10% increase in compile times that was in the May 10
nightly build compared to the May 8 nightly build (I've unpacked the
builds to check).
e.g. compiling Cabal with -O and ghc-20120508:
{{{
51,777,170,264 bytes allocated in the heap
10,213,181,272 bytes copied during GC
174,111,968 bytes maximum residency (57 sample(s))
6,843,024 bytes maximum slop
496 MB total memory in use (0 MB lost due to fragmentation)
Tot time (elapsed) Avg pause Max
pause
Gen 0 100232 colls, 0 par 25.37s 25.36s 0.0003s
0.0040s
Gen 1 57 colls, 0 par 13.46s 13.46s 0.2362s
0.5846s
INIT time 0.00s ( 0.00s elapsed)
MUT time 58.57s ( 61.82s elapsed)
GC time 38.82s ( 38.82s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 97.40s (100.65s elapsed)
}}}
and with ghc-20120510:
{{{
55,714,073,216 bytes allocated in the heap
11,751,752,512 bytes copied during GC
288,316,064 bytes maximum residency (51 sample(s))
8,407,960 bytes maximum slop
809 MB total memory in use (0 MB lost due to fragmentation)
Tot time (elapsed) Avg pause Max
pause
Gen 0 107660 colls, 0 par 28.91s 28.90s 0.0003s
0.0044s
Gen 1 51 colls, 0 par 16.56s 16.56s 0.3247s
1.0106s
INIT time 0.00s ( 0.00s elapsed)
MUT time 60.13s ( 63.20s elapsed)
GC time 45.47s ( 45.46s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 105.60s (108.67s elapsed)
}}}
we don't have a May 9 build because the change from mtl to transformers
broke it.
I've had a look at the patches that went in around that time, and these
are the only possible culprits as far as I can tell:
{{{
commit f7e246b50a33c329e9730296f7a342e03bc3db72
Merge: 4b089db... ff10612...
Author: Simon Peyton Jones <simo...@microsoft.com>
Date: Wed May 9 15:50:54 2012 +0100
Merge branch 'ghc-new-flavor'
commit 4bbd6baee066b906ed93a0659205ecbffdbd0954
Author: Simon Peyton Jones <simo...@microsoft.com>
Date: Fri May 4 23:02:46 2012 +0100
Simplify the SimplCont data type
commit e08cad76e8a434aca42996f79fc8bb790f291570
Author: Simon Peyton Jones <simo...@microsoft.com>
Date: Tue May 8 10:25:22 2012 +0100
Wibbles to 'simplify the SimplCont data type'
commit 2112f43c466935818a371c53c706608cfa069d01
Author: Simon Peyton Jones <simo...@microsoft.com>
Date: Wed May 9 11:06:44 2012 +0100
Be a little less aggressive about inlining (fixes Trac #5623)
commit 980372f357667c1ba63b28acbf5798826890b7a5
Author: Simon Peyton Jones <simo...@microsoft.com>
Date: Wed May 9 16:22:49 2012 +0100
Re-do the "function application discount" (fixes Trac #6048)
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6104#comment:3>
GHC <http://www.haskell.org/ghc/>
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