CRR: 7032531: G1: enhance GC logging to include more accurate eden / survivor size transitions (S/XS)

[Tony Printezis]

Thanks Bengt, I'll try to push asap!

On 06/08/2011 04:39 AM, Bengt Rutisson wrote:
>
> Tony,
>
> Looks good! I hope you get this in before I pick up the work on the 
> young space sizing. I will be useful to have this logging for that.
>
> Thanks,
> Bengt
>
>
> On 2011-06-07 20:10, Tony Printezis wrote:
>> Hi all,
>>
>> Could I have a couple of reviews for this change?
>>
>> http://cr.openjdk.java.net/~tonyp/7032531/webrev.0/
>>
>> This enhances the G1 +PrintGCDetails output to include how much space 
>> there is in the eden and survivor regions before / after a GC. Here's 
>> an example of the output:
>>
>>    [Eden: 18M->0B Survivors: 1024K->2048K Heap: 27M(105M)->12M(125M)]
>>
>> It shows that the eden had 18MB before the GC and it's empty after it 
>> (as expected!), the survivors were 1MB before the GC and grew to 2MB 
>> after the GC, the used space in the heap fell from 27MB to 12MB, and 
>> finally the heap size grew from 105MB to 125MB.
>>
>> Note that, currently, the eden / survivor sizes that are reported are 
>> not very accurate. They are currently calculated as region_num * 
>> region_size. It'd be better if they were calculated as the used byte 
>> total in the eden and survivor regions. But this would require a fair 
>> amount of extra changes to do (I'd rather avoid iterating over them 
>> to calculate that). We'll do that change when we revamp the region 
>> lists that keep track of the eden / survivor regions (which is 
>> currently work-in-progress).
>>
>> Tony
>>
>