use SkTDynamicHash in picture recording

use SkTDynamicHash in picture recording

cleaned up SkPictureFlat.h quite a bit while working on this.

bench --match picture_record_ shows some improvement:
compare.sh bench --match picture_record_ --repeat 100
master -> usehash
N=3 p=0.001000 (corrected to 0.000333)
sig? rel. speed  bench
  y      1.0x  picture_record_dictionaries
  y      1.5x  picture_record_recurring_paint_dictionary
  y      3.8x  picture_record_unique_paint_dictionary
Overall relative speed:   1.9x

bench_pictures --record is pretty much neutral:
compare.sh bench_pictures -r ../skp --mode record --repeat 30
master -> usehash
N=63 p=0.001000 (corrected to 0.000016)
sig? rel. speed  bench
  n      0.9x  desk_pokemonwiki.skp
  y      0.9x  desk_googlespreadsheet.skp
  y      0.9x  tabl_pravda.skp
  y      1.0x  desk_googlespreadsheetdashed.skp
  n      1.0x  tabl_onlinewsj.skp
  n      1.0x  tabl_nytimes.skp
  n      1.0x  desk_googlehome.skp
  y      1.0x  desk_techcrunch.skp
  n      1.0x  tabl_slashdot.skp
  n      1.0x  tabl_techmeme.skp
  n      1.0x  desk_googleplus.skp
  n      1.0x  desk_sfgate.skp
  n      1.0x  tabl_transformice.skp
  n      1.0x  desk_espn.skp
  n      1.0x  desk_baidu.skp
  n      1.0x  tabl_worldjournal.skp
  n      1.0x  desk_chalkboard.skp
  n      1.0x  tabl_frantzen.skp
  n      1.0x  desk_gws.skp
  n      1.0x  tabl_androidpolice.skp
  n      1.0x  desk_linkedin.skp
  n      1.0x  mobi_wikipedia.skp
  n      1.0x  desk_wowwiki.skp
  n      1.0x  desk_css3gradients.skp
  n      1.0x  desk_gmailthread.skp
  n      1.0x  desk_yahoogames.skp
  n      1.0x  desk_facebook.skp
  n      1.0x  desk_wordpress.skp
  n      1.0x  tabl_vnexpress.skp
  n      1.0x  desk_br337.skp
  n      1.0x  tabl_engadget.skp
  n      1.0x  tabl_theverge.skp
  n      1.0x  desk_amazon.skp
  n      1.0x  desk_ebay.skp
  n      1.0x  tabl_hsfi.skp
  n      1.0x  tabl_sahadan.skp
  n      1.0x  desk_weather.skp
  n      1.0x  tabl_digg.skp
  n      1.0x  desk_youtubetvbrowse.skp
  n      1.0x  tabl_culturalsolutions.skp
  n      1.0x  tabl_ukwsj.skp
  n      1.0x  desk_youtube.skp
  n      1.0x  tabl_googlecalendar.skp
  y      1.0x  desk_yahooanswers.skp
  n      1.0x  desk_blogger.skp
  n      1.0x  desk_yahoonews.skp
  y      1.0x  desk_yahoosports.skp
  y      1.0x  tabl_mercurynews.skp
  n      1.0x  desk_youtubetvvideo.skp
  y      1.0x  tabl_gspro.skp
  y      1.1x  tabl_googleblog.skp
  y      1.1x  tabl_cnet.skp
  y      1.1x  tabl_mlb.skp
  y      1.1x  tabl_cuteoverload.skp
  y      1.1x  desk_booking.skp
  y      1.1x  tabl_deviantart.skp
  y      1.1x  desk_twitter.skp
  y      1.1x  tabl_cnn.skp
  y      1.1x  tabl_gamedeksiam.skp
  y      1.1x  tabl_gmail.skp
  y      1.1x  tabl_nofolo.skp
  y      1.1x  tabl_mozilla.skp
  y      1.1x  desk_pinterest.skp
Overall relative speed:   1.0x

(I'd take this to mean that the microbenches are probably drifting away from relevance.)
BUG=
R=reed@google.com

Committed: https://code.google.com/p/skia/source/detail?r=10825

[mtklein, 2013-08-02 17:40:55]

Ah ha.

[10:33:27.728091] GM: ---- mixed_xfermodes_comparison-pipe.png: 47369 (of
505600) differing pixels, max per-channel mismatch R=73 G=181 B=65 A=0
[10:33:38.739389] ../src/core/SkTDynamicHash.h:178: failed assertion "success"

Please hold off on review until I sort out SkTDynamicHash or my use of it.

[tomhudson, 2013-08-05 10:27:00]

_recurring_ is the closest of the microbenches to relevance; it'd probably be
even better if ObjCount were 500. It isn't too hard to instrument Chrome to
sample a few websites & figure out what the right SkPaint reuse ratio is (my
memory of doing that in the past is where the 500 comes from, but the sample
size was small); you could probably throw lua at the big corpus and get a
histogram if you wanted.

[mtklein, 2013-08-05 15:28:15]

Okay, take a look Mike?

[reed1, 2013-08-05 15:43:28]

is the previous bench for scaledimagecache the same speed w/ this change? Are
you considering writing more tests/benches?

https://codereview.chromium.org/21564008/diff/19001/src/core/SkTDynamicHash.h
File src/core/SkTDynamicHash.h (right):

https://codereview.chromium.org/21564008/diff/19001/src/core/SkTDynamicHash.h...
src/core/SkTDynamicHash.h:21: SkTDynamicHash(int initialCapacity=64/sizeof(T*))
My scrape of the web sites showed a lot of font caches with 1..3 entries. Do you
think it is troublesome to support inline storage for small amounts?

https://codereview.chromium.org/21564008/diff/19001/src/core/SkTDynamicHash.h...
src/core/SkTDynamicHash.h:35: if (candidate == Empty()) return NULL;
prolly need to follow skia's "always use { }" rule for "ifs"

[mtklein, 2013-08-05 18:14:46]

Yep, imagecache bench doesn't change.  0.04 -> 0.04

This is the first time I noticed SkTDynamicHash doesn't have unit tests.  (I
should have noticed when I changed add's interface and it didn't break.)  I'll
add some and ping the thread.

https://codereview.chromium.org/21564008/diff/19001/src/core/SkTDynamicHash.h
File src/core/SkTDynamicHash.h (right):

https://codereview.chromium.org/21564008/diff/19001/src/core/SkTDynamicHash.h...
src/core/SkTDynamicHash.h:21: SkTDynamicHash(int initialCapacity=64/sizeof(T*))
On 2013/08/05 15:43:29, reed1 wrote:
> My scrape of the web sites showed a lot of font caches with 1..3 entries. Do
you
> think it is troublesome to support inline storage for small amounts?

Nope, was just trying to keep things simple with a single place for the data to
live.  (As for the default here, I figured a cache line would be the smallest
alloc worth doing, and it can't hurt to keep us on an integral number of them.) 
Personally I'd not pay the extra size cost of an fStorage before seeing a
performance difference.  Maybe we add a variant with local storage with an 'S'
shoved into the name somewhere?

https://codereview.chromium.org/21564008/diff/19001/src/core/SkTDynamicHash.h...
src/core/SkTDynamicHash.h:35: if (candidate == Empty()) return NULL;
On 2013/08/05 15:43:29, reed1 wrote:
> prolly need to follow skia's "always use { }" rule for "ifs"

ah, done.  That habit is dying hard.

[reed1, 2013-08-05 20:25:52]

Is there any value in making this 2 CLs?
1. update dynamichash.h and scaledimagecache
2. apply to pictures

[mtklein, 2013-08-05 23:11:16]

righto.  this is now just the second half

[reed1, 2013-08-07 12:08:38]

lgtm

[mtklein, 2013-08-20 16:48:54]

Committed patchset #15 manually as r10825 (presubmit successful).