On Wed, Oct 14, 2015 at 04:30:22PM -0400, Eric S. Johansson wrote: > On 10/14/2015 04:04 PM, Paolo Bonzini wrote: > >On 14/10/2015 21:39, Eric S. Johansson wrote: > >>Latency is a bit longer than I like. USB and network connections break > >>every time I come out of suspend part at least I don't have to use > >>Windows all the time. > >> > >> One thing is puzzling though. Windows, in idle, consume something like > >>15 to 20% CPU according to top. I turn on NaturallySpeaking, the > >>utilization climbs to him roughly 30 to 40%. I turn on the microphone > >>and utilization jumps up to 80-110%. In other words, it takes up a > >>whole core. > >USB is really expensive because it's all done through polling. Do that > >in hardware, and your computer is a bit hotter; do that in software > >(that's what VMs do) and your computer doubles as a frying pan. > > > >If you have USB3 drivers in Windows, you can try using a USB3 > >controller. But it's probably going to waste a lot of processing power > >too, because USB audio uses a lot of small packets, making it basically > >the worst case. > > Okay, then let's try to solve this a different way. What's the cleanest, > lowest latency way of delivering audio to a virtual machine that doesn't use > USB in the virtual machine? QEMU can emulate PCI soundcards, including the Intel HD Audio codec cards (-device intel-hda or -soundhw hda might do the trick). Low latency and power consumption are usually at odds with each other. That's because real-time audio requires small buffers many times per second, so lots of interrupts and power consumption. Anyway, PCI should be an improvement from USB audio. Stefan -- 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
