check a hashtable before using a bsearch

check a hashtable before using a bsearch
Committed: https://code.google.com/p/skia/source/detail?r=4572

[reed1, 2012-07-12 13:17:22]

picture_record_recurring_paint_dictionary went from 26 -> 18 msecs after this CL

[junov1, 2012-07-12 13:43:24]

lgtm, with comments.

https://codereview.appspot.com/6345097/diff/1/src/core/SkPictureFlat.h
File src/core/SkPictureFlat.h (right):

https://codereview.appspot.com/6345097/diff/1/src/core/SkPictureFlat.h#newcod...
src/core/SkPictureFlat.h:299: // Why do we have this check???
Good question. To be consistent with style guide, if we remove the check, I
think element should be by ref instead of ptr?

https://codereview.appspot.com/6345097/diff/1/src/core/SkPictureFlat.h#newcod...
src/core/SkPictureFlat.h:361: HASH_BITS   = 8,
Why 8?  IWBN to back this up with experimental data.
Perhaps log a bug to remind us to investigate this.

[reed1, 2012-07-12 14:49:07]

On 2012/07/12 13:43:24, junov1 wrote:
> lgtm, with comments.
> 
> https://codereview.appspot.com/6345097/diff/1/src/core/SkPictureFlat.h
> File src/core/SkPictureFlat.h (right):
> 
>
https://codereview.appspot.com/6345097/diff/1/src/core/SkPictureFlat.h#newcod...
> src/core/SkPictureFlat.h:299: // Why do we have this check???
> Good question. To be consistent with style guide, if we remove the check, I
> think element should be by ref instead of ptr?
> 
>
https://codereview.appspot.com/6345097/diff/1/src/core/SkPictureFlat.h#newcod...
> src/core/SkPictureFlat.h:361: HASH_BITS   = 8,
> Why 8?  IWBN to back this up with experimental data.
> Perhaps log a bug to remind us to investigate this.

Very good comment: I just made it up. I will try different values on our current
benchmarks, to see if smaller is good enough, or if larger helps. Regardless, I
will add a comment at least that this value is tweakable, and subject to current
needs.

[reed1, 2012-07-12 15:15:34]

patchset #2

- add comment and tweak HASH_BITS after testing (7 bits are enough for now)
- changed callers of find() to pass non-null ref

[Leon, 2012-07-12 15:18:19]

lgtm