VM: Fix snapshoting slow-down caused by 99c6a18a1bc2a4f13d8dd027a597fdca0f2d6e0c.

VM: Fix snapshoting slow-down caused by 99c6a18a1bc2a4f13d8dd027a597fdca0f2d6e0c.

Only reload packages map when we are actually doing the isolate reload.

Snapshotting creates and destroys and loader object every time it loads a dart
file - which means kInitLoader is on the hot path and we should avoid rereading
packages map.

R=asiva@google.com, rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/13f5616ef6012d01a2fa1c008241ea95c05bb57f

[siva, 2017-05-23 18:48:37]

asiva@google.com changed reviewers:
+ asiva@google.com

[siva, 2017-05-23 18:48:38]

LGTM to fix the regression.

We seem to have a bigger issue in that we create a loader object and call
Loader::Init everytime we issue Loader::SendAndProcessReply instead of setting
this up once for an isolate and using that. Will file an issue for this and
investigate why it is setup this way.

https://codereview.chromium.org/2901093002/diff/1/runtime/vm/dart_api_impl.cc
File runtime/vm/dart_api_impl.cc (right):

https://codereview.chromium.org/2901093002/diff/1/runtime/vm/dart_api_impl.cc...
runtime/vm/dart_api_impl.cc:6118: return true;
Should this be false as there is no reloading in PRODUCT mode?

[Vyacheslav Egorov (Google), 2017-05-23 20:00:48]

Thanks for the quick review.

I also find it strange that we reinitialize loader so often during snapshotting
and whenever we request kScript loading.

https://codereview.chromium.org/2901093002/diff/1/runtime/vm/dart_api_impl.cc
File runtime/vm/dart_api_impl.cc (right):

https://codereview.chromium.org/2901093002/diff/1/runtime/vm/dart_api_impl.cc...
runtime/vm/dart_api_impl.cc:6118: return true;
On 2017/05/23 18:48:37, siva wrote:
> Should this be false as there is no reloading in PRODUCT mode?

Yep, this was a typo.

I fixed it in the local checkout but only after I uploaded CL.

[Vyacheslav Egorov (Google), 2017-05-23 20:01:48]

Description was changed from

==========
VM: Fix snapshoting slow-down caused by
99c6a18a1bc2a4f13d8dd027a597fdca0f2d6e0c.

Only reload packages map when we are actually doing the isolate reload.

Snapshotting creates and destroys and loader object every time it loads a dart
file - which means kInitLoader is on the hot path and we should avoid rereading
packages map.

R=rmacnak@google.com
==========

to

==========
VM: Fix snapshoting slow-down caused by
99c6a18a1bc2a4f13d8dd027a597fdca0f2d6e0c.

Only reload packages map when we are actually doing the isolate reload.

Snapshotting creates and destroys and loader object every time it loads a dart
file - which means kInitLoader is on the hot path and we should avoid rereading
packages map.

R=asiva@google.com, rmacnak@google.com

Committed:
https://github.com/dart-lang/sdk/commit/13f5616ef6012d01a2fa1c008241ea95c05bb57f
==========

[Vyacheslav Egorov (Google), 2017-05-23 20:01:49]

Committed patchset #1 (id:1) manually as
13f5616ef6012d01a2fa1c008241ea95c05bb57f.