Multi-survivor support for SVM GC

[Doug Simon]

Hi Tongbao,

Such a contribution sounds very interesting. Please submit a PR to https://github.com/oracle/graal so we can discuss further.

-Doug 

> On 22 Nov 2019, at 14:24, 张同宝(井桐) <tongbao.ztb at alibaba-inc.com> wrote:
> 
> Dear Graal developers,
> 
> Substrate VM is a great framework to generate executable native images for Java applications. Thank you for making it open-source.
> We (Alibaba) are trying to use Substrate VM and native-image to speed up the startup of our cloud-based Java applications.
> 
> Meantime, we also found problems when running our applications using SVM.
> The full GC occurred more frequently than the HotSpot VM because there are no object age and survivor spaces in the current SVM GC implementation.
> 
> We made some improvements to the SVM GC to address these problems, which can significantly decrease the full GC frequency.
> We would like to contribute a patch to the community, including the multi-survivor support of SVM builtin GC to reduce the frequency of full GC.
> We have tested this patch thoroughly in our production environment and are glad to contribute it to the Graal community.
> 
> Look forward to your response.
> 
> Thanks,
> Tongbao Zhang