Re: [rvm-research] Pre-Tenuring

There is one large object space. Objects larger than a threshold are pre-tenured to the large object space as in all default generational collectors. That is perfectly fine!

Small objects go to the nursery, with the exception that, objects of type T go to the mature (immix) space. Note that in default generational collectors, there is no such pre-tenuring. This is my modification.

Pre-tenuring objects of type T creates the problem.

What I am guessing is that when the GC tries to copy objects from nursery to immix mature space, that creates a problem. 

I am not new to Jikes and have a list of steps that I can follow to get to the root of this. But being in an emergency, I wanted some quick tips in case some one has tried similar things ;)

Sorry for possibly missing more details.

> On Aug 10, 2018, at 7:17 PM, Eliot Moss <[email protected]> wrote:
> 
> On 8/10/2018 12:04 PM, Shoaib Akram wrote:
>> Hi All,
>> Hello again from Ghent! Something that should be a cakewalk is giving me a headache.
>> I want to pre-tenure certain objects. In MemoryManager, instead of assigning ALLOC_DEFAULT, I check the classes of objects and choose instead ALLOC_MATURE. This happens during compilation.
>> Anyway, what’s next is the mutator checks the allocator changing it to LOS if the object is large.
>> In GenImmixMutator, I use the mature allocator to allocate into the mature space.
>> Pretty straightforward really.
>> But it does not work.
>> Before I embark on the debugging process, I wonder if anyone has advice what step could be missing here. Or any synchronization issues that may arise.
>> Thanks,
>> Shoaib
> 
> Dear Shoaib -- Is it only *large* ALLOC_MATURE objects that fail, or *all* ALLOC_MATURE objects?
> Or what?  I could not figure out what you're trying to tell us.  Also, what is the LOS
> configuration?  Only one LOS, or one for MATURE and non-MATURE?  Or something else?
> 
> I can't claim to be expert on the innards here, but I think that a clearer question / problem
> description may focus better the answers you can expect ...
> 
> Regards - Eliot Moss
> 
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