Hi Peter --
As I understand it (and my knowledge only stretches as far as the bigsurv.ps
paper and the Richard Jones Garbage Collection book), the way a garbage
collector interacts with virtual memory is an issue whether it's at the OS
level (JJOS, JavaOS) or at the application level ('normal' Java running on
existing OS). However, as you'll in read in bigsurv.ps, the GC community is
well aware of these issues and modern garbage collectors are designed with
attention given to minimising swapping. Some types of moving GC can even
improve VM performance, by grouping frequently accessed objects together on
the same page, thus decreasing the size of the working set. To move down a
level again, there's quite a bit of space in both bigsurv.ps and the book
given to looking at how GC interacts with the processor's cache.
For the record, the GC I'm working on at the moment doesn't do anything
clever to avoid swapping - but that's OK, because JJOS doesn't do swapping
yet :-)
-- George
> -----Original Message-----
> From: [EMAIL PROTECTED] [SMTP:[EMAIL PROTECTED]]
> Sent: Wednesday, August 04, 1999 11:39
> To: [EMAIL PROTECTED]
> Subject: [JOS-Kernel] GC and swap space
>
> Hi!
>
> I'm curious; has any thought been given to how garbage collection will
> work
> on a system that uses swap space (i.e. 99% of them)?
>
> I'm in *NO* way an expert on GC (I've only started reading that bigsurv.ps
> that someone mentioned), but it seems to be that it will be very hard to
> to implement a garbage collector capable of performing GC on a system half
> of whose virtual RAM consists of swap space. It looks to me like at least
> occatoinal thrashing is unavoidable.
>
> Is it even *possible*? Does JavaOS do it, and if so, how?
>
> Just curious...
>
> --
> / Peter Schuller
>
> PGP userID: 0x5584BD98 or 'Peter Schuller <[EMAIL PROTECTED]>'
> Key retrival: Send an E-Mail to [EMAIL PROTECTED]
> E-Mail: [EMAIL PROTECTED] Web: http://hem.passagen.se/petersch
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