Speedup profile generation for stress test benchmark by 176x

Speedup profile generation for stress test benchmark by 176x

Processed 779753 frames
CodeTables: live=9604 dead=5345 tag=51

FixTopFrame took 158092 millis.
CodeRegionTableBuilder took 13616 millis.
CodeRegionExclusiveTrieBuilder took 283 millis.
CodeRegionTableCallersBuilder took 57 millis.
CodeTableStream took 5637 millis.

~176 seconds

--- Fix PageSpace::FindObject to fast path executable pages

Processed 648584 frames
CodeTables: live=9398 dead=4655 tag=45

FixTopFrame took 68401 millis.
CodeRegionTableBuilder took 6401 millis.
CodeRegionExclusiveTrieBuilder took 222 millis.
CodeRegionTableCallersBuilder took 45 millis.
CodeTableStream took 267 millis.

~74 seconds

--- Fix PageSpace::Contains to fast path executable pages

Processed 690756 frames
CodeTables: live=9329 dead=5310 tag=49

FixTopFrame took 234 millis.
CodeRegionTableBuilder took 173 millis.
CodeRegionExclusiveTrieBuilder took 265 millis.
CodeRegionTableCallersBuilder took 60 millis.
CodeTableStream took 331 millis.

~1 second

R=iposva@google.com

Committed: https://code.google.com/p/dart/source/detail?r=42672

[Cutch, 2015-01-07 20:48:44]

johnmccutchan@google.com changed reviewers:
+ iposva@google.com

[Ivan Posva, 2015-01-07 21:35:04]

LGTM -ip

https://codereview.chromium.org/839833003/diff/20001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://codereview.chromium.org/839833003/diff/20001/runtime/vm/pages.cc#newc...
runtime/vm/pages.cc:446: // Provides exclusive access to code pages, and ensures
they are walkable.
Please make a note in the comment that this iterator only iterates of the
regular sized code pages.

[Cutch, 2015-01-07 21:38:03]

https://codereview.chromium.org/839833003/diff/20001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://codereview.chromium.org/839833003/diff/20001/runtime/vm/pages.cc#newc...
runtime/vm/pages.cc:446: // Provides exclusive access to code pages, and ensures
they are walkable.
On 2015/01/07 21:35:04, Ivan Posva wrote:
> Please make a note in the comment that this iterator only iterates of the
> regular sized code pages.

Done.

[Cutch, 2015-01-07 21:39:57]

Committed patchset #3 (id:40001) manually as 42672 (presubmit successful).