Take 2 : CRR: 7027766: G1: introduce flag to dump the liveness information per region at the end of marking (S)

Tony Printezis tony.printezis at oracle.com
Tue Mar 29 16:21:15 UTC 2011

Hi all,

First, thanks to Igor for a very prompt review.

After I opened the previous version for code review I realized that if 
we want to create any graphs based on this information having the 
information about all the regions in a humongous region series grouped 
into a single region (which is what I did before) will make the parser 
work a bit harder to extract the per-region information (and we'd like 
that information to track what happens to an individual region over 
time). So, I changed the output format to show the information for 
humongous regions separately for each individual region.

Here's a quick summary of the changes:

- Now there are two tags for humongous regions: HUMS (starts humongous) 
and HUMC (continues humongous)
- I removed the capacity per-region as now all the regions have the same 
capacity which is the region size. So we can save some space there.
- Minor cosmetic changes.
- I actually turned the flag off by default (I had accidentally set its 
default value to true before).

Latest webrev here:


I attached example output from the new workspace (64-bit this time, and 
I made sure it also includes some humongous regions).


Tony Printezis wrote:
> Hi,
> I'd like a couple of reviewers to have a look at this change:
> http://cr.openjdk.java.net/~tonyp/7027766/webrev.0/
> I ended up repurposing the existing develop flag 
> G1PrintRegionLivenessInfo for this (I had actually forgotten it was 
> there!) and I print the liveness information at the end of marking twice:
> - Info for all regions after we finalize the marking information, 
> which means we have both the latest marking information as well as the 
> previous marking information available.
> - The same info but for all sorted old regions.
> I attached example output.
> Tony
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