review for 7029167: add support for conditional card marks

[Igor Veresov]

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.


igor

On 3/30/11 4:46 PM, Tom Rodriguez wrote:
> http://cr.openjdk.java.net/~never/7029167
>
> 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.
>