Repository : ssh://g...@git.haskell.org/bytestring
On branch : ghc-head
Link :
http://git.haskell.org/packages/bytestring.git/commitdiff/8279acae79e45b0cdb9a154c1a2fbb78ab4480d3
>---------------------------------------------------------------
commit 8279acae79e45b0cdb9a154c1a2fbb78ab4480d3
Author: Duncan Coutts <dun...@community.haskell.org>
Date: Sat Oct 5 20:06:38 2013 +0100
Fix documentation of memory overheads
>---------------------------------------------------------------
8279acae79e45b0cdb9a154c1a2fbb78ab4480d3
Data/ByteString/Short.hs | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/Data/ByteString/Short.hs b/Data/ByteString/Short.hs
index 02ac0be..4248417 100644
--- a/Data/ByteString/Short.hs
+++ b/Data/ByteString/Short.hs
@@ -36,16 +36,16 @@ module Data.ByteString.Short (
-- | With GHC, the memory overheads are as follows, expressed in words and
-- in bytes (words are 4 and 8 bytes on 32 or 64bit machines respectively).
--
- -- * 'ByteString' unshared: 7 words; 28 or 56 bytes.
+ -- * 'ByteString' unshared: 9 words; 36 or 72 bytes.
--
-- * 'ByteString' shared substring: 5 words; 20 or 40 bytes.
--
- -- * 'ShortByteString': 3 words; 12 or 24 bytes.
+ -- * 'ShortByteString': 4 words; 16 or 32 bytes.
--
-- For the string data itself, both 'ShortByteString' and 'ByteString' use
-- one byte per element, rounded up to the nearest word. For example,
-- including the overheads, a length 10 'ShortByteString' would take
- -- @12 + 12 = 24@ bytes on a 32bit platform and @24 + 16 = 40@ bytes on a
+ -- @16 + 12 = 28@ bytes on a 32bit platform and @32 + 16 = 48@ bytes on a
-- 64bit platform.
--
-- These overheads can all be reduced by 1 word (4 or 8 bytes) when the
@@ -53,11 +53,12 @@ module Data.ByteString.Short (
--
-- For example:
--
- -- > data ThingyId = ThingyId {-# UNPACK #-} !Int
- -- > {-# UNPACK #-} !ShortByteString
+ -- > data ThingId = ThingId {-# UNPACK #-} !Int
+ -- > {-# UNPACK #-} !ShortByteString
--
- -- This will take @1 + 1 + 2@ words (the constructor + unpacked @Int@ +
- -- unpacked @ShortByteString@), plus the words for the string data.
+ -- This will take @1 + 1 + 3@ words (the @ThingId@ constructor +
+ -- unpacked @Int@ + unpacked @ShortByteString@), plus the words for the
+ -- string data.
-- ** Heap fragmentation
-- | With GHC, the 'ByteString' representation uses /pinned/ memory,
_______________________________________________
ghc-commits mailing list
ghc-commits@haskell.org
http://www.haskell.org/mailman/listinfo/ghc-commits
