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Type: Enhancement
Resolution: Fixed
Priority: P4
Fix Version/s: 9
Affects Version/s: None
Component/s: hotspot
Labels:
- performance

Subcomponent:
gc
Resolved In Build:
b42

Issue	Fix Version	Assignee	Priority	Status	Resolution	Resolved In Build
JDK-8083247	emb-9	Staffan Friberg	P4	Resolved	Fixed	team
JDK-8086443	8u65	Staffan Friberg	P4	Resolved	Fixed	b01
JDK-8075812	8u60	Staffan Friberg	P4	Resolved	Fixed	b09
JDK-8137638	emb-8u65	Unassigned	P4	Resolved	Fixed	b01
JDK-8077458	emb-8u60	Staffan Friberg	P4	Resolved	Fixed	team

The current G1 object copy implementation reads age multiple times from the object being promoted/copied which is a fairly expensive operation as it is reading a volatile and requires using a mask to access the age bits.

To avoid this the markOop will read before the check if the object has already been copied and then the age is read once and reused when updating the age of the object if the thread ends up copying it.

backported by

JDK-8075812 Improved handling of age during object copy in G1

Resolved

JDK-8077458 Improved handling of age during object copy in G1

Resolved

JDK-8083247 Improved handling of age during object copy in G1

Resolved

JDK-8086443 Improved handling of age during object copy in G1

Resolved

JDK-8137638 Improved handling of age during object copy in G1

Resolved

duplicates

JDK-8059837 G1 may not tenure objects after MaxTenuringThreshold young GCs

Closed

relates to

JDK-8198310 G1 does not properly age objects with displaced marks

Closed

(1 duplicates, 1 relates to)

Assignee:: Staffan Friberg (Inactive)

Reporter:: Staffan Friberg (Inactive)

Votes:: 0 Vote for this issue

Watchers:: 2 Start watching this issue

Created:: 2014-11-10 08:17

Updated:: 2018-02-16 12:45

Resolved:: 2014-11-17 03:04

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