> 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.
In the applications, probably very independent. In the kernel, highly dependent: different CPUs may access shared data structures *and* protect them with spinlocks. As Paul said in a separate mail, spinlocks are going to be way more expensive in this sort of distributed environment. All that being said, a company called "Virtual Iron" has got a fully-virtualising solution that presents an SMP to the guest OS but actually distributes computation across a cluster. I have yet to see the product itself - no idea when it'll be released. It also sounds *really* difficult to make go fast but at least suggests this sort of thing can perform reasonably for some workloads. Cheers, Mark > > 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 _______________________________________________ Qemu-devel mailing list Qemu-devel@nongnu.org http://lists.nongnu.org/mailman/listinfo/qemu-devel
