dart2js: Reduce overhead of --verbose measurements

dart2js: Reduce overhead of --verbose measurements

ZoneSpecification and zoneValues are now per-task, rather than per measurement.
This reduces total LinkedHashMap allocations by 30%

In the large compile I am using to measure these things, there are still
~3M zones created via Zone.fork and 10M _ZoneFunction objects allocated, and the Zone.fork copies the (now cached) LinkedHashMap.
So cross-task measurements are still quite expensive.

R=ahe@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/101a83f2f465edfa60b4e013ad53b0868ce99b89

[sra1, 2016-07-09 01:39:05]

Description was changed from

==========
dart2js: Reduce overhead of --verbose measurements

ZoneSpecification and zoneValues are now per-task, rather than per measurement.
This reduces total LinkedHashMap allocations by 30%

R=ahe@google.com
BUG=
==========

to

==========
dart2js: Reduce overhead of --verbose measurements

ZoneSpecification and zoneValues are now per-task, rather than per measurement.
This reduces total LinkedHashMap allocations by 30%

In the large compile I am using to measure these things, there are still
~3M zones created via Zone.fork and 10M _ZoneFunction objects allocated, and the
Zone.fork copies the (now cached) LinkedHashMap.
So cross-task measurements are still quite expensive.

R=ahe@google.com
BUG=
==========

[sra1, 2016-07-09 01:39:26]

Peter, what do you think?

[ahe, 2016-08-04 17:17:33]

lgtm

That's a neat idea.

https://codereview.chromium.org/2133913002/diff/1/pkg/compiler/lib/src/common...
File pkg/compiler/lib/src/common/tasks.dart (right):

https://codereview.chromium.org/2133913002/diff/1/pkg/compiler/lib/src/common...
pkg/compiler/lib/src/common/tasks.dart:106: ZoneSpecification
_zoneSpecification;
I would move the fields up with the other fields of this class.

[sra1, 2016-08-08 21:18:31]

Description was changed from

==========
dart2js: Reduce overhead of --verbose measurements

ZoneSpecification and zoneValues are now per-task, rather than per measurement.
This reduces total LinkedHashMap allocations by 30%

In the large compile I am using to measure these things, there are still
~3M zones created via Zone.fork and 10M _ZoneFunction objects allocated, and the
Zone.fork copies the (now cached) LinkedHashMap.
So cross-task measurements are still quite expensive.

R=ahe@google.com
BUG=
==========

to

==========
dart2js: Reduce overhead of --verbose measurements

ZoneSpecification and zoneValues are now per-task, rather than per measurement.
This reduces total LinkedHashMap allocations by 30%

In the large compile I am using to measure these things, there are still
~3M zones created via Zone.fork and 10M _ZoneFunction objects allocated, and the
Zone.fork copies the (now cached) LinkedHashMap.
So cross-task measurements are still quite expensive.

R=ahe@google.com
BUG=

Committed:
https://github.com/dart-lang/sdk/commit/101a83f2f465edfa60b4e013ad53b0868ce99b89
==========

[sra1, 2016-08-08 21:18:33]

Committed patchset #2 (id:20001) manually as
101a83f2f465edfa60b4e013ad53b0868ce99b89 (presubmit successful).