[GHC] #12629: Worse performance with -O1 or -O2 due to GC cost
#12629: Worse performance with -O1 or -O2 due to GC cost -------------------------------------+------------------------------------- Reporter: onex | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs g a = replicate (n-a) (a+1) f [x] = [[x]] f list = [ a:b | a <- list, b <- f $ g a] main = do print $ length $ f [1..12] }}} The function ''g'' can be replaced by any ''a -> [a]'' function. Without optimization: {{{ 94,885,791,728 bytes allocated in the heap 280,050,384 bytes copied during GC 62,432 bytes maximum residency (18 sample(s)) 27,144 bytes maximum slop 2 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 182071 colls, 0 par 0.437s 0.442s 0.0000s 0.0004s Gen 1 18 colls, 0 par 0.000s 0.002s 0.0001s 0.0004s INIT time 0.000s ( 0.002s elapsed) MUT time 14.992s ( 15.188s elapsed) GC time 0.437s ( 0.444s elapsed) RP time 0.000s ( 0.000s elapsed) PROF time 0.000s ( 0.000s elapsed) EXIT time 0.000s ( 0.000s elapsed) Total time 15.428s ( 15.634s elapsed) %GC time 2.8% (2.8% elapsed) Alloc rate 6,329,223,264 bytes per MUT second Productivity 97.2% of total user, 95.9% of total elapsed }}} With -O2: {{{ 86,218,852,592 bytes allocated in the heap 13,323,597,456 bytes copied during GC 62,712 bytes maximum residency (12895 sample(s)) 47,104 bytes maximum slop 2 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 154129 colls, 0 par 6.724s 6.685s 0.0000s 0.0015s Gen 1 12895 colls, 0 par 0.484s 0.479s 0.0000s 0.0004s INIT time 0.000s ( 0.001s elapsed) MUT time 12.714s ( 13.002s elapsed) GC time 7.207s ( 7.164s elapsed) RP time 0.000s ( 0.000s elapsed) PROF time 0.000s ( 0.000s elapsed) EXIT time 0.000s ( 0.000s elapsed) Total time 19.921s ( 20.167s elapsed) %GC time 36.2% (35.5% elapsed) Alloc rate 6,781,366,989 bytes per MUT second Productivity 63.8% of total user, 63.0% of total elapsed }}} System:Windows/macOS Compiler:8.0.1/7.10.3 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12629 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#12629: Worse performance with -O1 or -O2 due to GC cost -------------------------------------+------------------------------------- Reporter: onex | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by onex: @@ -2,0 +2,2 @@ + n = 11 + @@ -8,1 +10,1 @@ - print $ length $ f [1..12] + print $ length $ f [1..n] New description: {{{#!hs n = 11 g a = replicate (n-a) (a+1) f [x] = [[x]] f list = [ a:b | a <- list, b <- f $ g a] main = do print $ length $ f [1..n] }}} The function ''g'' can be replaced by any ''a -> [a]'' function. Without optimization: {{{ 94,885,791,728 bytes allocated in the heap 280,050,384 bytes copied during GC 62,432 bytes maximum residency (18 sample(s)) 27,144 bytes maximum slop 2 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 182071 colls, 0 par 0.437s 0.442s 0.0000s 0.0004s Gen 1 18 colls, 0 par 0.000s 0.002s 0.0001s 0.0004s INIT time 0.000s ( 0.002s elapsed) MUT time 14.992s ( 15.188s elapsed) GC time 0.437s ( 0.444s elapsed) RP time 0.000s ( 0.000s elapsed) PROF time 0.000s ( 0.000s elapsed) EXIT time 0.000s ( 0.000s elapsed) Total time 15.428s ( 15.634s elapsed) %GC time 2.8% (2.8% elapsed) Alloc rate 6,329,223,264 bytes per MUT second Productivity 97.2% of total user, 95.9% of total elapsed }}} With -O2: {{{ 86,218,852,592 bytes allocated in the heap 13,323,597,456 bytes copied during GC 62,712 bytes maximum residency (12895 sample(s)) 47,104 bytes maximum slop 2 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 154129 colls, 0 par 6.724s 6.685s 0.0000s 0.0015s Gen 1 12895 colls, 0 par 0.484s 0.479s 0.0000s 0.0004s INIT time 0.000s ( 0.001s elapsed) MUT time 12.714s ( 13.002s elapsed) GC time 7.207s ( 7.164s elapsed) RP time 0.000s ( 0.000s elapsed) PROF time 0.000s ( 0.000s elapsed) EXIT time 0.000s ( 0.000s elapsed) Total time 19.921s ( 20.167s elapsed) %GC time 36.2% (35.5% elapsed) Alloc rate 6,781,366,989 bytes per MUT second Productivity 63.8% of total user, 63.0% of total elapsed }}} System:Windows/macOS Compiler:8.0.1/7.10.3 -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12629#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#12629: Worse performance with -O1 or -O2 due to GC cost -------------------------------------+------------------------------------- Reporter: onex | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by onex: @@ -2,1 +2,1 @@ - n = 11 + n = 12 New description: {{{#!hs n = 12 g a = replicate (n-a) (a+1) f [x] = [[x]] f list = [ a:b | a <- list, b <- f $ g a] main = do print $ length $ f [1..n] }}} The function ''g'' can be replaced by any ''a -> [a]'' function. Without optimization: {{{ 94,885,791,728 bytes allocated in the heap 280,050,384 bytes copied during GC 62,432 bytes maximum residency (18 sample(s)) 27,144 bytes maximum slop 2 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 182071 colls, 0 par 0.437s 0.442s 0.0000s 0.0004s Gen 1 18 colls, 0 par 0.000s 0.002s 0.0001s 0.0004s INIT time 0.000s ( 0.002s elapsed) MUT time 14.992s ( 15.188s elapsed) GC time 0.437s ( 0.444s elapsed) RP time 0.000s ( 0.000s elapsed) PROF time 0.000s ( 0.000s elapsed) EXIT time 0.000s ( 0.000s elapsed) Total time 15.428s ( 15.634s elapsed) %GC time 2.8% (2.8% elapsed) Alloc rate 6,329,223,264 bytes per MUT second Productivity 97.2% of total user, 95.9% of total elapsed }}} With -O2: {{{ 86,218,852,592 bytes allocated in the heap 13,323,597,456 bytes copied during GC 62,712 bytes maximum residency (12895 sample(s)) 47,104 bytes maximum slop 2 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 154129 colls, 0 par 6.724s 6.685s 0.0000s 0.0015s Gen 1 12895 colls, 0 par 0.484s 0.479s 0.0000s 0.0004s INIT time 0.000s ( 0.001s elapsed) MUT time 12.714s ( 13.002s elapsed) GC time 7.207s ( 7.164s elapsed) RP time 0.000s ( 0.000s elapsed) PROF time 0.000s ( 0.000s elapsed) EXIT time 0.000s ( 0.000s elapsed) Total time 19.921s ( 20.167s elapsed) %GC time 36.2% (35.5% elapsed) Alloc rate 6,781,366,989 bytes per MUT second Productivity 63.8% of total user, 63.0% of total elapsed }}} System:Windows/macOS Compiler:8.0.1/7.10.3 -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12629#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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