On 21 Oct 2009, at 15:41, Eliot Moss wrote:

As indicated in paul's survey, to implement advancement policies in
copying GC, we need to create an "age" information in header field.
Could anyone be kind to tell me where this information is stored in RVM?

It's not there by default, AFAIK. It you want a collector to do that,
you would need to design an age field into the header, etc. It's
possible, but I think a lot of us have generally felt that we might
as well have more generations rather than paw over the same object
multiple times before promoting it.

Although this is exactly what HotSpot does as far as I recall.

Also not that you don't have to encode age by putting it in the header. You can also encode it by address (which can allow fractional ages).

As for putting it in the header, MiscHeader.java is the place to look

Richard


Maybe some of the MMTK folk can wiegh in on this question?

Best wishes -- Eliot Moss

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Richard Jones | Reader in Computer Systems | University of Kent
Computing Laboratory, University of Kent, Canterbury, Kent CT2 7NF, UK
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