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Re: Improve zone allocator allocation performance


This is okay
Thanks!

On Aug 23, 2004, at 4:22 PM, Daniel Jacobowitz wrote:

This patch brings the zone allocator roughly to par with the page allocator.

A brief comparison, all boostrapped with --disable-checking:
Patch OK?

--
Daniel Jacobowitz

2004-08-23 Daniel Jacobowitz <dan@debian.org>

	* ggc-zone.c (struc alloc_chunk): Rearrange flag bits and SIZE.
	Remove TYPECODE.
	(ggc_alloc_zone_1): Mark TYPE as unused.  Don't save it in the chunk.

Index: ggc-zone.c
===================================================================
RCS file: /home/drow/rsync/gcc-cvs/gcc/gcc/ggc-zone.c,v
retrieving revision 2.18
diff -u -p -r2.18 ggc-zone.c
--- ggc-zone.c	9 Aug 2004 23:11:08 -0000	2.18
+++ ggc-zone.c	23 Aug 2004 20:16:06 -0000
@@ -146,10 +146,13 @@ struct alloc_chunk {
   unsigned int magic;
 #endif
   unsigned int type:1;
-  unsigned int typecode:14;
-  unsigned int large:1;
-  unsigned int size:15;
   unsigned int mark:1;
+  unsigned char large;
+  unsigned short size;
+  /* Right now, on 32-bit hosts we don't have enough room to save the
+     typecode unless we make the one remaining flag into a bitfield.
+     There's a performance cost to that, so we don't do it until we're
+     ready to use the type information for something.  */
   union {
     struct alloc_chunk *next_free;
     char data[1];
@@ -594,7 +597,8 @@ free_chunk (struct alloc_chunk *chunk, s
 /* Allocate a chunk of memory of SIZE bytes.  */

static void *
-ggc_alloc_zone_1 (size_t orig_size, struct alloc_zone *zone, short type
+ggc_alloc_zone_1 (size_t orig_size, struct alloc_zone *zone,
+ short type ATTRIBUTE_UNUSED
MEM_STAT_DECL)
{
size_t bin = 0;
@@ -696,7 +700,8 @@ ggc_alloc_zone_1 (size_t orig_size, stru
#endif
chunk->type = 1;
chunk->mark = 0;
- chunk->typecode = type;
+ /* We could save TYPE in the chunk, but we don't use that for
+ anything yet. */
result = chunk->u.data;


#ifdef ENABLE_GC_CHECKING


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