On Tue, 2005-05-17 at 21:21 +0100, Paul Brook wrote:
> > What inter processor synchronization issues are there? Could you take
> > this a step further and use processes on different machines for each
> > processor? (There are many shared memory implementations to choose
> > from.) Are there so many resources shared
> > between the CPUs to make this a ridiculous proposition?
>
> Baically most SMP/shared memory systems assume very low latency communication
> between CPUs and memory. For example on opteron systems remote memory latency
> is of the order of 200 cpu cycles. Typical ethernet latency is several
> million cycles.
But how often will the virtual CPUs need the same page and is there any
other shared resource other than memory? I don't know how independent
each CPU is. Though in side discussions, everyone agrees with you, I
haven't seen numbers to convince my gut. If page only needs to be
faulted back and forth every couple million cycles, then it might work.
> The only solution I can imagine being even vaguely worthwhile is a running
> user-mode qemu on top of a native openmozix system.
OpenMosix is very interesting, but is a pain to setup. How about this:
ssh -f host1 qemu -cpu-server $KEY
ssh -f host2 qemu -cpu-server $KEY
qemu -cpu-client host1:$KEY \
-cpu-client host2:$KEY \
-hda server.image
> > I have ignorantly implemented an SH2 emulator,
>
> Cool. Any chance you're going to make these changes publicly available?
It was a Java implementation for a customer. Not my property and not
integrated with any free software.
> Paul
--
Joe Batt <[EMAIL PROTECTED]>
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