#5535: Performance regression vs. 7.2.1
---------------------------------+------------------------------------------
Reporter: simonmar | Owner:
Type: bug | Status: new
Priority: highest | Milestone: 7.4.1
Component: Compiler | Version: 7.2.1
Keywords: | Testcase:
Blockedby: | Difficulty:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: None/Unknown
---------------------------------+------------------------------------------
`nofib/spectral/mandel` is showing a regression since 7.2.1.
Create a larger test input:
{{{
$ cat >mandel.in
-2.0
-2.0
2.0
2.0
512
512
256
}}}
With today's 7.3:
{{{
$ ./mandel <mandel.in +RTS -s >/dev/null
Enter min x = Enter min y = Enter max x = Enter max y = Screen width =
Screen height= Screen depth = 3,517,780,112 bytes allocated in the heap
21,178,480 bytes copied during GC
98,960 bytes maximum residency (19 sample(s))
42,640 bytes maximum slop
2 MB total memory in use (0 MB lost due to fragmentation)
Tot time (elapsed) Avg pause Max
pause
Gen 0 6736 colls, 0 par 0.11s 0.11s 0.0000s
0.0002s
Gen 1 19 colls, 0 par 0.00s 0.00s 0.0001s
0.0003s
INIT time 0.00s ( 0.00s elapsed)
MUT time 2.92s ( 2.92s elapsed)
GC time 0.11s ( 0.11s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 3.03s ( 3.03s elapsed)
}}}
With 7.2.1:
{{{
$ ./mandel <mandel.in +RTS -s >/dev/null
Enter min x = Enter min y = Enter max x = Enter max y = Screen width =
Screen height= Screen depth = 2,554,096,496 bytes allocated in the heap
16,583,464 bytes copied during GC
98,928 bytes maximum residency (16 sample(s))
44,216 bytes maximum slop
2 MB total memory in use (0 MB lost due to fragmentation)
Tot time (elapsed) Avg pause Max
pause
Gen 0 4919 colls, 0 par 0.08s 0.08s 0.0000s
0.0002s
Gen 1 16 colls, 0 par 0.00s 0.00s 0.0001s
0.0003s
INIT time 0.00s ( 0.00s elapsed)
MUT time 2.29s ( 2.29s elapsed)
GC time 0.08s ( 0.08s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 2.37s ( 2.37s elapsed)
}}}
Both were standard builds (`GhcLibOpts` contains -O2), and the programs
themselves were compiled with -O2.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5535>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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