Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 21 Dec 2009 17:43:09 +0200 | From | Avi Kivity <> | Subject | Re: [GIT PULL] AlacrityVM guest drivers for 2.6.33 |
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On 12/21/2009 05:34 PM, Gregory Haskins wrote: > >> I think it would be fair to point out that these patches have been objected to >> by the KVM folks quite extensively, >> > Actually, these patches have nothing to do with the KVM folks. You are > perhaps confusing this with the hypervisor-side discussion, of which > there is indeed much disagreement. >
This is true, though these drivers are fairly pointless for virtualization without the host side support.
I did have a few issues with the guest drivers: - the duplication of effort wrt virtio. These drivers don't cover exactly the same problem space, but nearly so. - no effort at scalability - all interrupts are taken on one cpu - the patches introduce a new virtual interrupt controller for dubious (IMO) benefits
> From my research, the reason why virt in general, and KVM in particular > suffers on the IO performance front is as follows: IOs > (traps+interrupts) are more expensive than bare-metal, and real hardware > is naturally concurrent (your hbas and nics are effectively parallel > execution engines, etc). > > Assuming my observations are correct, in order to squeeze maximum > performance from a given guest, you need to do three things: A) > eliminate as many IOs as you possibly can, B) reduce the cost of the > ones you can't avoid, and C) run your algorithms in parallel to emulate > concurrent silicon. >
All these are addressed by vhost-net without introducing new drivers.
-- error compiling committee.c: too many arguments to function
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