On Thu, Sep 16, 2010 at 12:13:32PM +0200, Gleb Natapov wrote: > On Thu, Sep 16, 2010 at 11:53:10AM +0200, Michael S. Tsirkin wrote: > > On Thu, Sep 16, 2010 at 11:46:03AM +0200, Avi Kivity wrote: > > > On 09/16/2010 11:25 AM, Gleb Natapov wrote: > > > >> > > > >> MSI only appeared in rhel6, older guests still use level interrupts. > > > >So they are already slow for other reasons. > > > > > > > > > > Exactly, for example they need to exit to userspace to ack the > > > interrupt. That's far slower than the workqueue. > > > > Well, this is not exactly comparable: you might get > > same irq asserted multiple times and only deasserted once. > > > Are we talking about level interrupts? Why would you assert level > triggered interrupt multiple times before deasserting it? User of irqfd has no way to know what current interrupt level is. So it has to keep asserting. > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
