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Issue metadata

Status: Assigned
HW: ----
NextAction: ----
OS: All
Priority: 2
Type: Bug

Blocked on:
issue 5459
issue 3664

issue 2935

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Issue 3665: Allocation site pretenuring degrades performance in Ember

Reported by, Oct 30 2014 Project Member

Issue description

v8:3664 tracks deoptimizations caused by weak references. With disabled weak references, allocation site pretenuring is the next common cause of deoptimization.

"Complex List" test at runs
- 185.11ms without weak references, with allocation site pretenuring (--js-flags="--noweak-embedded-objects-in-optimized-code --noweak-embedded-maps-in-optimized-code")
- 169.57ms without weak references and without allocation site pretenuring (--js-flags="--noweak-embedded-objects-in-optimized-code --noweak-embedded-maps-in-optimized-code --noallocation-site-pretenuring")

Comment 1 by, Oct 30 2014

Blocking: v8:2935

Comment 2 by, Apr 29 2015

Status: Assigned

Comment 3 by, Nov 14 2015

Any progress on this?

Comment 4 by, Nov 15 2015

Yes, months ago we tried disabling allocation site pretenuring, so that none of these deopts occur. The performance effect was negligible. Deopts occurred in those functions anyway, for other reasons.

Comment 5 by, Oct 8 2016

Blockedon: 5459

Comment 6 by, Mar 23 2017

Labels: Priority-2

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