On Thu, Jul 31, 2014 at 01:16:06PM +0800, Kmindg wrote:
> ovstest test-bitmap benchmark 100000 (without this commit):
> bitmap equal: 52 ms
> bitmap scan: 758 ms
>
> ovstest test-bitmap benchmark 100000 (with this commit):
> bitmap equal: 37 ms
> bitmap scan: 34 ms
>
> Tested on Intel Xeon E5-2620 v2 @ 2.10GHz
>
> Signed-off-by: Kmindg <[email protected]>
I'm pretty sure that this first check in bitmap_scan():
+ if (t && count) {
+ /* 'start' is not aligned to BITMAP_ULONG_BITS. */
+ v = *bitmap_unit__(bitmap, start) >> t;
+
+ idx = bitmap_scan__(v, target);
+ if (idx < BITMAP_ULONG_BITS - t) {
+ return idx + start;
+ }
+ count -= BITMAP_ULONG_BITS - t;
+ start += BITMAP_ULONG_BITS - t;
+ }
could cause bitmap_scan() to return a value greater than 'end'.
bitmap_scan() seems to use 't' for two very different purposes. Please
use different variables for different purposes.
bitmap_scan() seems to return 'start' if it is unsuccessful, rather than
'end'.
These apparent bugs don't make me feel confident about the tests.
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