[HACKERS] [PATCH 2/2] Use fls() to find chunk set

[Jeremy Kerr]

Results in a ~2% performance increase by using the powerpc fls()
implementation.

Signed-off-by: Jeremy Kerr <j...@ozlabs.org>

---
 src/backend/utils/mmgr/aset.c |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/src/backend/utils/mmgr/aset.c b/src/backend/utils/mmgr/aset.c
index 0e2d4d5..762cf72 100644
--- a/src/backend/utils/mmgr/aset.c
+++ b/src/backend/utils/mmgr/aset.c
@@ -65,6 +65,7 @@
 #include "postgres.h"
 
 #include "utils/memutils.h"
+#include "utils/bitops.h"
 
 /* Define this to detail debug alloc information */
 /* #define HAVE_ALLOCINFO */
@@ -270,12 +271,7 @@ AllocSetFreeIndex(Size size)
 
        if (size > 0)
        {
-               size = (size - 1) >> ALLOC_MINBITS;
-               while (size != 0)
-               {
-                       idx++;
-                       size >>= 1;
-               }
+               idx = fls((size - 1) >> ALLOC_MINBITS);
                Assert(idx < ALLOCSET_NUM_FREELISTS);
        }
 

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