RFR (S) 8246100: Shenandoah: walk roots in more efficient order

[Zhengyu Gu]

On 6/2/20 5:52 AM, Aleksey Shipilev wrote:
> On 6/1/20 9:26 PM, Zhengyu Gu wrote:
>> Wait, should we process CLDG early? CLD likely uneven, e.g. boot class
>> loader may take a lot longer than others.
> 
> It is not uneven in my tests. But even if it is, we want to do CLDG before thread/code roots, which
> is what the patch does. With 8246097, it would be moved to the "lightweight/limited" block before.
> 
>> On 6/1/20 3:03 PM, Zhengyu Gu wrote:
>>> Looks good in general. But not sure why call vm/weak/dedup roots limited
>>> parallel, I think they are fully parallel.
> 
> Yes. But they are also lightweight, that's what block does: both lightweight or limited-parallel.
> 

Okay, then.

-Zhengyu

>>>> Webrev:
>>>>     https://cr.openjdk.java.net/~shade/8246100/webrev.02/
>