c54581e · streamly · git.iko.soy

git.iko.soy/streamly

Improve performance of parseMany

1. Make the parser state strict so that it can fuse. 2. Use special paths for "Continue 0" and "Done 0" cases Overall improvement from 440 us (6GB allocations) to 175 us (22 MB allocations).

commitc54581ee95e3ab6ac91e3c7c8e11287f00ae3fc7 authorHarendra Kumar <harendra@composewell.com> dateWed 21 Oct 2020, 20:19 (6 years ago) parenta94ec36

1 file changed+11−7

compare with master

unifiedsplit

src/Streamly/Internal/Data/Stream/StreamD.hs+11−7

src/Streamly/Internal/Data/Stream/StreamD.hs+11−7

@@ -1029,8 +1029,8 @@ parselMx' pstep initial extract (Stream step state) = do

10291029data ParseChunksState x inpBuf st pst =

10301030 ParseChunksInit inpBuf st

10311031 | ParseChunksInitLeftOver inpBuf

1032− | ParseChunksStream st inpBuf pst

1033− | ParseChunksBuf inpBuf st inpBuf pst

1032+ | ParseChunksStream st inpBuf !pst

1033+ | ParseChunksBuf inpBuf st inpBuf !pst

10341034 | ParseChunksYield x (ParseChunksState x inpBuf st pst)

10351035

10361036{-# INLINE_NORMAL parseMany #-}

@@ -1075,14 +1075,16 @@ parseMany (PRD.Parser pstep initial extract) (Stream step state) =

10751075 let src0 = Prelude.take n (x:buf)

10761076 src = Prelude.reverse src0

10771077 return $ Skip $ ParseChunksBuf src s [] pst1

1078− -- PR.Continue 0 pst1 ->

1079− -- return $ Skip $ ParseChunksStream s (x:buf) pst1

1078+ PR.Continue 0 pst1 ->

1079+ return $ Skip $ ParseChunksStream s (x:buf) pst1

10801080 PR.Continue n pst1 -> do

10811081 assert (n <= length (x:buf)) (return ())

10821082 let (src0, buf1) = splitAt n (x:buf)

10831083 src = Prelude.reverse src0

10841084 return $ Skip $ ParseChunksBuf src s buf1 pst1

1085− -- XXX Specialize for Stop 0 common case?

1085+ PR.Done 0 b -> do

1086+ return $ Skip $

1087+ ParseChunksYield b (ParseChunksInit [] s)

10861088 PR.Done n b -> do

10871089 assert (n <= length (x:buf)) (return ())

10881090 let src = Prelude.reverse (Prelude.take n (x:buf))

@@ -1111,13 +1113,15 @@ parseMany (PRD.Parser pstep initial extract) (Stream step state) =

11111113 let src0 = Prelude.take n (x:buf)

11121114 src = Prelude.reverse src0 ++ xs

11131115 return $ Skip $ ParseChunksBuf src s [] pst1

1114− -- PR.Continue 0 pst1 -> return $ Skip $ ParseChunksBuf xs s (x:buf) pst1

1116+ PR.Continue 0 pst1 ->

1117+ return $ Skip $ ParseChunksBuf xs s (x:buf) pst1

11151118 PR.Continue n pst1 -> do

11161119 assert (n <= length (x:buf)) (return ())

11171120 let (src0, buf1) = splitAt n (x:buf)

11181121 src = Prelude.reverse src0 ++ xs

11191122 return $ Skip $ ParseChunksBuf src s buf1 pst1

1120− -- XXX Specialize for Stop 0 common case?

1123+ PR.Done 0 b ->

1124+ return $ Skip $ ParseChunksYield b (ParseChunksInit xs s)

11211125 PR.Done n b -> do

11221126 assert (n <= length (x:buf)) (return ())

11231127 let src = Prelude.reverse (Prelude.take n (x:buf)) ++ xs