Request for review (S): 7037276: Unnecessary double traversal of dirty card windows

[Y. Srinivas Ramakrishna]

I discovered a small flaw in this which I am going to fix.
If you have not started your review yet, please hold off
until I publish a second version of the changeset that
fixes the flaw I found.

Sorry for not having found this earlier and for the delay.
-- ramki

On 4/18/2011 11:34 AM, Y. Srinivas Ramakrishna wrote:
>
> I'd like a couple of code reviews for:
>
> 7037276: Unnecessary double traversal of dirty card windows
> http://cr.openjdk.java.net/~ysr/7037276/webrev.00/
>
> Card scanning with ParNew and DefNew scavenges was collecting
> dirty card windows in one method and then doing a retraversal
> of that window in another method to clear the cards and iterate
> over the refs on those cards. This double traversal was unnecessary,
> since the collection of contiguous ranges, their clearing and the
> iteration over the covered refs could all be done in a single sweep
> over the cards covering the region of interest.
>
> I also specialized some of the arguments to these calls,
> made some internal methods private and renamed a few others
> for greater clarity.
>
> This is the second of a series of about 4 CRs aimed at eventually
> fixing 6883834 (the last in the series). Stay tuned for some
> more incremental rearrangements of related code in another
> one or two subsequent CRs.
>
> A quick performance measurement didn't show any appreciable
> change in scavenge times as a result of this change, but more
> careful performance measurements are in progress.
>
> Tested with jprt, the test case for 6883834 and refworkload server.
> Perf measurements with refworkload server in progress.
>
> thanks for your reviews.
> -- ramki