a096f77 · streamly · git.iko.soy

git.iko.soy/streamly

Round up space to 4K for large objects

In shrinkToFit. Also, rename shrinkToFit to rightSize.

commita096f77c3e3032b2f8f27e291d52a18bd2ab1a18 authorHarendra Kumar <harendra@composewell.com> dateMon 11 Oct 2021, 22:59 (5 years ago) parent8f467a4

3 files changed+24−14

compare with master

unifiedsplit

src/Streamly/Internal/Data/Array/Foreign/Mut/Type.hs+21−11 src/Streamly/Internal/Data/Array/Foreign/Type.hs+2−2 src/Streamly/Internal/Data/Array/Stream/Foreign.hs+1−1

src/Streamly/Internal/Data/Array/Foreign/Mut/Type.hs+21−11

@@ -29,7 +29,7 @@ module Streamly.Internal.Data.Array.Foreign.Mut.Type

2929

3030 -- * Resizing

3131 , realloc

32− , shrinkToFit

32+ , rightSize

3333

3434 -- * Size

3535 , length

@@ -533,18 +533,28 @@ realloc i arr =

533533 $ reallocAligned

534534 (sizeOf (undefined :: a)) (alignment (undefined :: a)) i arr

535535

536−-- | Remove the free space from an Array.

537−{-# INLINE shrinkToFit #-}

538−shrinkToFit :: (MonadIO m, Storable a) => Array a -> m (Array a)

539−shrinkToFit arr@Array{..} = do

536+-- | Drop any reserved free space at the end of the array and reallocate it to

537+-- reduce wastage.

538+--

539+-- Up to 25% wastage is allowed to avoid reallocations. If the capacity is

540+-- more than 'largeObjectThreshold' then free space up to the 'blockSize' is

541+-- retained.

542+--

543+-- /Pre-release/

544+{-# INLINE rightSize #-}

545+rightSize :: forall m a. (MonadIO m, Storable a) => Array a -> m (Array a)

546+rightSize arr@Array{..} = do

540547 assert (aEnd <= aBound) (return ())

541548 let start = unsafeForeignPtrToPtr aStart

542− let used = aEnd `minusPtr` start

549+ len = aEnd `minusPtr` start

550+ capacity = aBound `minusPtr` start

551+ target = roundUpLargeArray len

543552 waste = aBound `minusPtr` aEnd

544− -- if used == waste == 0 then do not realloc

545− -- if the wastage is more than 25% of the array then realloc

546− if used < 3 * waste

547− then realloc used arr

553+ assert (target >= len) (return ())

554+ assert (len `mod` sizeOf (undefined :: a) == 0) (return ())

555+ -- We trade off some wastage (25%) to avoid reallocations and copying.

556+ if target < capacity && len < 3 * waste

557+ then realloc target arr

548558 else return arr

549559

550560-------------------------------------------------------------------------------

@@ -1106,7 +1116,7 @@ writeWith alignSize elemCount =

11061116 (sizeOf (undefined :: a)) alignSize newSize arr

11071117 insertElem arr1 x

11081118 step arr x = insertElem arr x

1109− extract = liftIO . shrinkToFit

1119+ extract = liftIO . rightSize

11101120

11111121-- | Fold the whole input to a single array.

11121122--

src/Streamly/Internal/Data/Array/Foreign/Type.hs+2−2

@@ -170,12 +170,12 @@ foreign import ccall unsafe "string.h strlen" c_strlen

170170unsafeFreeze :: MA.Array a -> Array a

171171unsafeFreeze (MA.Array as ae _) = Array as ae

172172

173−-- | Similar to 'unsafeFreeze' but uses 'MA.shrinkToFit' on the mutable array

173+-- | Similar to 'unsafeFreeze' but uses 'MA.rightSize' on the mutable array

174174-- first.

175175{-# INLINE unsafeFreezeWithShrink #-}

176176unsafeFreezeWithShrink :: Storable a => MA.Array a -> Array a

177177unsafeFreezeWithShrink arr = unsafePerformIO $ do

178− MA.Array as ae _ <- MA.shrinkToFit arr

178+ MA.Array as ae _ <- MA.rightSize arr

179179 return $ Array as ae

180180

181181-- | Makes a mutable array using the underlying memory of the immutable array.

src/Streamly/Internal/Data/Array/Stream/Foreign.hs+1−1

@@ -474,7 +474,7 @@ spliceArraysRealloced s = do

474474 (mkChunkSizeKB 4))

475475

476476 arr <- S.foldlM' MA.spliceExp idst (S.map A.unsafeThaw s)

477− liftIO $ A.unsafeFreeze <$> MA.shrinkToFit arr

477+ liftIO $ A.unsafeFreeze <$> MA.rightSize arr

478478

479479-- XXX This should just be "fold A.write"

480480--