Re: CoW memory and Parallax questions.

[Jacob Faber Kloster <jk@cs.aau.dk>]

On Mon, 2005-10-03 at 12:12 -0700, Kip Macy wrote:
> They aren't mutually exclusive, but a content-based approach, although
> more flexible, seems like it would inevitably be much heavier weight. 
> What is your solution targeted towards?
> 
>  -Kip              

Indeed a combination of the two could be in order to avoid some
unnecessary processing. Also there is no doubt that content based
sharing uses more processing time, but it is more generally applicable
than the 'forking' scheme. For instance it seems hard to come up with a
scheme that allows sharing of memory when migrating VMs. Furthermore as
VMs, in the forking scheme, have run for a longer period of time, we
expect the percent of sharing to decrease. Content based sharing will
allow us to identify sharing that was not possible at the time of
forking.

Our solution is thus meant as an option when starting several VMs that
are similar, but not identical from start. Perhaps the processing
overhead of doing content based sharing is too large, but we can't
really know for certain before we have done some experiments.

Best regards
Jacob Faber Kloster (group email d515a@cs.aau.dk)