review for 7029167: add support for conditional card marks

Tom Rodriguez tom.rodriguez at
Wed Mar 30 17:10:56 PDT 2011

On Mar 30, 2011, at 5:03 PM, Vladimir Kozlov wrote:

> Tom,
> what about arraycopy stubs?

I don't think they are necessary.  This is really about the performance of concurrent algorithms that are doing a lot of field updates, not eliminating all redundant card marks.


> Vladimir
> Tom Rodriguez wrote:
>> 7029167: add support for conditional card marks
>> Reviewed-by:
>> Repeated updates to the card table can be a source of contention on
>> multiprocessor machines that can greatly inhibit scalability.  This
>> adds support in C2 for conditional card marks.  Tested with jbb and
>> CTW.  At some point this should be turned on automatically when multi
>> socket machines are detected but that's covered under another bug as
>> is C1 support.

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