Bug 165910

Summary:

Make the collector's fixpoint smart about scheduling work

Product:

WebKit

Reporter:

Filip Pizlo <fpizlo>

Component:

JavaScriptCore

Assignee:

Filip Pizlo <fpizlo>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

commit-queue

Priority:

Version:

WebKit Nightly Build

Hardware:

All

OS:

All

Bug Depends on:

165911, 165963

Bug Blocks:

165909, 166828, 166827, 166831

Attachments:

Description	Flags
possible patch	none
the patch	none
the patch	none
the patch	keith_miller: review+

Filip Pizlo

Reported 2016-12-15 12:18:54 PST

The GC currently scans a bunch of things in each fixpoint iteration. It will sometimes do many fixpoint iterations. I suspect that when it does have to perform multiple fixpoint iterations, it's because some specific part of the fixpoint is being very needy. This implies that we can dramatically improve the fixpoint's performance using traditional fixpoint optimization tricks.

Attachments
possible patch (145.25 KB, patch) 2017-01-08 11:54 PST, Filip Pizlo	no flags	Details Formatted Diff Diff
the patch (148.03 KB, patch) 2017-01-08 14:27 PST, Filip Pizlo	no flags	Details Formatted Diff Diff
the patch (148.26 KB, patch) 2017-01-08 15:32 PST, Filip Pizlo	no flags	Details Formatted Diff Diff
the patch (148.27 KB, patch) 2017-01-08 15:46 PST, Filip Pizlo	keith_miller: review+	Details Formatted Diff Diff
Show Obsolete (3) View All Add attachment proposed patch, testcase, etc.

Filip Pizlo

Comment 1 2016-12-15 14:49:12 PST

I'm imagining that each of the phases of the weak fixpoint would be put into a SharedTask or some even smarter object, and then we'd be able to write some scheduler that runs them in an order that reduces the average number of executions.

Filip Pizlo

Comment 2 2017-01-08 11:34:10 PST

*** Bug 165963 has been marked as a duplicate of this bug. ***

Filip Pizlo

Comment 3 2017-01-08 11:36:33 PST

I was originally thinking that in bug 165963, I would implement the infrastructure that's needed to intelligently schedule work and then in this bug I would use that infrastructure to get an optimization. I ended up doing both of those things in bug 165963.

Filip Pizlo

Comment 4 2017-01-08 11:54:29 PST

Created attachment 298310 [details] possible patch

Filip Pizlo

Comment 5 2017-01-08 14:27:22 PST

Created attachment 298316 [details] the patch

WebKit Commit Bot

Comment 6 2017-01-08 14:29:15 PST

Attachment 298316 [details] did not pass style-queue: ERROR: Source/JavaScriptCore/heap/MarkingConstraintSet.cpp:201: An else statement can be removed when the prior "if" concludes with a return, break, continue or goto statement. [readability/control_flow] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:37: Code inside a namespace should not be indented. [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:37: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:38: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:39: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:40: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:49: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:50: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:51: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:52: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:53: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] Total errors found: 11 in 27 files If any of these errors are false positives, please file a bug against check-webkit-style.

Filip Pizlo

Comment 7 2017-01-08 15:32:38 PST

Created attachment 298320 [details] the patch

WebKit Commit Bot

Comment 8 2017-01-08 15:35:45 PST

Attachment 298320 [details] did not pass style-queue: ERROR: Source/JavaScriptCore/heap/MarkingConstraintSet.cpp:201: An else statement can be removed when the prior "if" concludes with a return, break, continue or goto statement. [readability/control_flow] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:37: Code inside a namespace should not be indented. [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:37: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:38: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:39: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:40: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:49: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:50: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:51: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:52: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:53: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] Total errors found: 11 in 27 files If any of these errors are false positives, please file a bug against check-webkit-style.

Filip Pizlo

Comment 9 2017-01-08 15:46:06 PST

Created attachment 298321 [details] the patch

WebKit Commit Bot

Comment 10 2017-01-08 15:48:54 PST

Attachment 298321 [details] did not pass style-queue: ERROR: Source/JavaScriptCore/heap/MarkingConstraintSet.cpp:201: An else statement can be removed when the prior "if" concludes with a return, break, continue or goto statement. [readability/control_flow] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:37: Code inside a namespace should not be indented. [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:37: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:38: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:39: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:40: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:49: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:50: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:51: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:52: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] ERROR: Source/JavaScriptCore/heap/MarkingConstraint.cpp:53: Wrong number of spaces before statement. (expected: 8) [whitespace/indent] [4] Total errors found: 11 in 27 files If any of these errors are false positives, please file a bug against check-webkit-style.

Keith Miller

Comment 11 2017-01-09 12:57:06 PST

Comment on attachment 298321 [details] the patch View in context: https://bugs.webkit.org/attachment.cgi?id=298321&action=review r=me with some minor comments. > Source/JavaScriptCore/heap/MarkingConstraintSet.cpp:124 > +void MarkingConstraintSet::add( > + std::unique_ptr<MarkingConstraint> constraint) Nit, put this on one line. > Source/JavaScriptCore/heap/SpaceTimeMutatorScheduler.cpp:2 > + * Copyright (C) 2016 Apple Inc. All rights reserved. 2017 > Source/JavaScriptCore/heap/SpaceTimeMutatorScheduler.h:2 > + * Copyright (C) 2016 Apple Inc. All rights reserved. 2017

Filip Pizlo

Comment 12 2017-01-09 12:58:41 PST

(In reply to comment #11) > Comment on attachment 298321 [details] > the patch > > View in context: > https://bugs.webkit.org/attachment.cgi?id=298321&action=review > > r=me with some minor comments. > > > Source/JavaScriptCore/heap/MarkingConstraintSet.cpp:124 > > +void MarkingConstraintSet::add( > > + std::unique_ptr<MarkingConstraint> constraint) > > Nit, put this on one line. Done. > > > Source/JavaScriptCore/heap/SpaceTimeMutatorScheduler.cpp:2 > > + * Copyright (C) 2016 Apple Inc. All rights reserved. > > 2017 You're commenting on the pseudofile that the patch is showing you. In fact, SpaceTimeMutatorScheduler.cpp:2 is: * Copyright (C) 2016-2017 Apple Inc. All rights reserved. > > > Source/JavaScriptCore/heap/SpaceTimeMutatorScheduler.h:2 > > + * Copyright (C) 2016 Apple Inc. All rights reserved. > > 2017 Ditto.

Filip Pizlo

Comment 13 2017-01-09 13:48:27 PST

Landed in https://trac.webkit.org/changeset/210521

Filip Pizlo

Comment 14 2017-01-09 16:16:31 PST

Fixed cloop in https://trac.webkit.org/changeset/210530

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