[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PROPOSAL] Event channel for SMP-VMs: per-vCPU or per-OS?
On Tue, Oct 29, 2013 at 11:21 PM, David Vrabel <dvrabel@xxxxxxxxxx> wrote:
Thanks for your echoing, David.
Sure, but if the interrupt handler is not called timely, no irq threads will be created. I don't see any way this could be implemented using the 2-level ABI. Probably the implementation does not need to bother 2-level ABI. With the FIFO ABI, queues cannot move between VCPUs without some I think it is the hypervisor who plays the role of deciding which vCPU should be kicked to serve I/O. Different routing policies results in different results. Since all vCPUs are symmetrically scheduled, the events can therefore be
evenly distributed onto them. At one moment, vCPUx is running, while at another moment, vCPUy is running. So, the events will not always crowd to very few ones. Currently, all I/O events are bound to vCPU0, which is just like what you said:
events would crowd onto that vCPU. As a result, vCPU0 consumes much more CPU cycles than other ones, leading to unfairness. If some workload can be dynamically migrated to other vCPUs, I believe more or less we can get
some benefit. Thanks, Luwei _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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