RFR (S): 8049341: Parallelize clearing the next mark bitmap

[Marcus Larsson]

Hi again,

Updated the changeset to a more recent version, with changes suggested 
by Mikael.

Webrev:
http://cr.openjdk.java.net/~mgerdin/mlarsson/webrev-8049341v2/

Marcus

On 08/28/2014 01:06 PM, Marcus Larsson wrote:
> Hi,
>
> I would like reviews for the following patch to parallelize the 
> clearing of the next mark bitmap in G1.
>
> Short summary:
> The heap is divided into as many parts as there are workers and each 
> worker will clear its corresponding part of the bitmap. Workers will 
> join the suspendible thread set instead of the concurrent mark thread 
> to properly allow them to yield during clearing work. Added support 
> for applying heap region closures to a specific part of the heap. 
> SPECjbb2013 shows a slight performance gain with this change (4%, 
> using 4 concurrent threads).
>
> Webrev:
> http://cr.openjdk.java.net/~brutisso/webrev-8049341/
>
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8049341
>
> Testing:
> jprt, SPECjbb2013, SPECjbb2005, SPECjvm2008
>
> Thanks,
> Marcus