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Re: PING [patch] malloc: add mxfast tunable
On 8/8/19 5:04 PM, Florian Weimer wrote:
* DJ Delorie:
+@deftp Tunable glibc.malloc.mxfast
+One of the optimizations malloc uses is to maintain a series of ''fast
+bins'' that hold chunks up to a specific size. The default and
+maximum size which may be held this way is 80 bytes on 32-bit systems
+or 160 bytes on 64-bit systems. Applications which value size over
+speed may choose to reduce the number of fast bins with this tunable.
+Note that the value specified includes malloc's internal overhead,
+which is normally the size of one pointer, so add 4 on 32-bit systems
+or 8 on 64-bit systems to the size passed to @code{malloc} for the
+largest bin size to enable.
+@end deftp
I think the quotes are wrong, they should be `` '' (ASCII, Texinfo will
transform them). Or you could use @dfn and add an index entry.
Does the fastbin range depend on pointer or size or minimum malloc
alignment? The latter is 16 bytes on some 32-bit architectures, even
though it is usually 8 bytes.
Entirely on SIZE_SZ.
/* The maximum fastbin request size we support */
#define MAX_FAST_SIZE (80 * SIZE_SZ / 4)
--
Cheers,
Carlos.