#6110: Data.Vector.Unboxed performance regression of 7.4.1 relative to 7.0.4
----------------------------------------------+-----------------------------
Reporter: mdgabriel | Owner: pcapriotti
Type: bug | Status: infoneeded
Priority: high | Milestone: 7.4.3
Component: Compiler | Version: 7.4.1
Keywords: Vector Performance Regression | Os: Linux
Architecture: x86 | Failure: Runtime
performance bug
Difficulty: Unknown | Testcase:
Blockedby: | Blocking:
Related: #6111 |
----------------------------------------------+-----------------------------
Comment(by mdgabriel):
'''Profiling'''
SCC was used for profiling ghc 7.0.4 and 7.4.1:
{{{
putSum :: Int -> IO ()
putSum cnt = let f = {-# SCC "fromIntegral" #-} (\i -> fromIntegral i ::
Double)
v = {-# SCC "U.generate" #-} U.generate cnt f
s = {-# SCC "U.sum" #-} U.sum v
in putStrLn ("Sum="++show s)
}}}
Profiling using '-prof -auto-all' with ghc 7.0.4:
{{{
Fri Jun 22 19:00 2012 Time and Allocation Profiling Report
(Final)
sum704prof +RTS -p -RTS 100000000
total time = 45.54 secs (2277 ticks @ 20 ms)
total alloc = 14,800,016,380 bytes (excludes profiling overheads)
COST CENTRE MODULE %time %alloc
U.generate Main 46.9 35.1
U.sum Main 31.2 40.5
fromIntegral Main 21.9 24.3
individual inherited
COST CENTRE MODULE
no. entries %time %alloc %time %alloc
MAIN MAIN
1 0 0.0 0.0 100.0 100.0
CAF Main
300 2 0.0 0.0 100.0 100.0
main Main
306 1 0.0 0.0 100.0 100.0
putSum Main
307 1 0.0 0.0 100.0 100.0
U.sum Main
310 1 31.2 40.5 31.2 40.5
U.generate Main
309 1 46.9 35.1 46.9 35.1
fromIntegral Main
308 100000000 21.9 24.3 21.9 24.3
CAF GHC.Float
277 1 0.0 0.0 0.0 0.0
CAF Text.Read.Lex
266 4 0.0 0.0 0.0 0.0
CAF GHC.IO.Handle.FD
236 2 0.0 0.0 0.0 0.0
CAF GHC.IO.Encoding.Iconv
194 2 0.0 0.0 0.0 0.0
CAF GHC.Conc.Signal
191 1 0.0 0.0 0.0 0.0
CAF Data.Vector.Unboxed
182 1 0.0 0.0 0.0 0.0
}}}
Profiling using '-prof -auto-all' with ghc 7.4.1:
{{{
Fri Jun 22 19:09 2012 Time and Allocation Profiling Report
(Final)
sum741prof +RTS -p -RTS 100000000
total time = 44.55 secs (44550 ticks @ 1000 us, 1
processor)
total alloc = 15,600,082,056 bytes (excludes profiling overheads)
COST CENTRE MODULE %time %alloc
U.sum Main 34.3 38.5
U.generate Main 31.0 38.5
putSum.f.\ Main 24.9 23.1
putSum.f Main 5.8 0.0
fromIntegral Main 3.9 0.0
individual
inherited
COST CENTRE MODULE no. entries %time %alloc
%time %alloc
MAIN MAIN 67 0 0.0 0.0
100.0 100.0
CAF Main 133 0 0.0 0.0
100.0 100.0
main Main 134 1 0.0 0.0
100.0 100.0
putSum Main 135 1 0.0 0.0
100.0 100.0
putSum.f Main 140 1 0.0 0.0
0.0 0.0
fromIntegral Main 141 1 0.0 0.0
0.0 0.0
putSum.v Main 138 1 0.0 0.0
65.7 61.5
U.generate Main 139 1 31.0 38.5
65.7 61.5
putSum.f Main 142 0 5.8 0.0
34.7 23.1
fromIntegral Main 143 0 3.9 0.0
28.9 23.1
putSum.f.\ Main 144 100000000 24.9 23.1
24.9 23.1
putSum.s Main 136 1 0.0 0.0
34.3 38.5
U.sum Main 137 1 34.3 38.5
34.3 38.5
CAF GHC.Conc.Signal 111 0 0.0 0.0
0.0 0.0
CAF Text.Read.Lex 104 0 0.0 0.0
0.0 0.0
CAF GHC.Float 101 0 0.0 0.0
0.0 0.0
CAF GHC.IO.Encoding 100 0 0.0 0.0
0.0 0.0
CAF GHC.IO.Encoding.Iconv 94 0 0.0 0.0
0.0 0.0
CAF GHC.IO.Handle.FD 92 0 0.0 0.0
0.0 0.0
}}}
'''Statistics'''
Statistics for sum compiled with ghc 7.0.4:
{{{
./sum704 1000000000 +RTS -ssum704-stats.txt
74,836 bytes allocated in the heap
1,440 bytes copied during GC
42,316 bytes maximum residency (1 sample(s))
23,220 bytes maximum slop
1 MB total memory in use (0 MB lost due to fragmentation)
Generation 0: 0 collections, 0 parallel, 0.00s, 0.00s elapsed
Generation 1: 1 collections, 0 parallel, 0.00s, 0.00s elapsed
INIT time 0.00s ( 0.00s elapsed)
MUT time 7.42s ( 7.46s elapsed)
GC time 0.00s ( 0.00s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 7.43s ( 7.46s elapsed)
%GC time 0.0% (0.0% elapsed)
Alloc rate 10,078 bytes per MUT second
Productivity 100.0% of total user, 99.5% of total elapsed
}}}
Statistics for sum compiled with ghc 7.4.1:
{{{
./sum741 1000000000 +RTS -ssum741-stats.txt
87,864 bytes allocated in the heap
1,756 bytes copied during GC
42,632 bytes maximum residency (1 sample(s))
18,808 bytes maximum slop
1 MB total memory in use (0 MB lost due to fragmentation)
Tot time (elapsed) Avg pause Max
pause
Gen 0 0 colls, 0 par 0.00s 0.00s 0.0000s
0.0000s
Gen 1 1 colls, 0 par 0.00s 0.00s 0.0002s
0.0002s
INIT time 0.00s ( 0.00s elapsed)
MUT time 17.55s ( 17.69s elapsed)
GC time 0.00s ( 0.00s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 17.55s ( 17.69s elapsed)
%GC time 0.0% (0.0% elapsed)
Alloc rate 5,006 bytes per MUT second
Productivity 100.0% of total user, 99.2% of total elapsed
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6110#comment:13>
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