On 02/21/2011 10:16 AM, Paolo Bonzini wrote:
On 02/21/2011 04:13 AM, wang sheng wrote:
What is the purpose of io_thread desigment in qemu ?
There was a lengthy thread recently explaining how it helps fixing a
possibly delay in handling I/O. It is also useful for KVM, where you
have one I/O thread and multiple CPU threads. This way, KVM can
implement "real" SMP (i.e. multiple virtual CPUs running concurrently).
In fact kvm smp was available even before the iothread; one thread
handled both vcpu 0 and I/O completions, while the other threads only
handled a vcpu each. Later, the first thread was split into an iothread
and a vcpu 0 thread.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
