review for 7029167: add support for conditional card marks
igor.veresov at oracle.com
Wed Mar 30 17:35:54 PDT 2011
On 3/30/11 5:33 PM, Tom Rodriguez wrote:
> On Mar 30, 2011, at 5:25 PM, Igor Veresov wrote:
>> Looks good.
>> Could you use CardTableModRefBS::dirty_card_val() instead of 0? I know we use just zero already in many places, but I'm fresh from barrier experimentation and it would've been much nicer if we used symbolic names.
> I'd rather not. If we really want to use dirty_card_val then it should be done everywhere as its own change instead of just patching part of C2.
May be a comment then, saying that ConI(0) represents dirty_card ? Just
for the sake of future grepping?
>> On 3/30/11 4:46 PM, Tom Rodriguez wrote:
>>> 7029167: add support for conditional card marks
>>> 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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