Hi Paige
I noticed your -cpu option does not disable hypervisor; you might want to try it, please see http://vfio.blogspot.co.uk/2016/10/how-to-improve-performance-in-windows-7.html for reference. On the example of my virtual machines, this translates to qemu options: -machine pc-i440fx-2.5,accel=kvm,usb=off,dump-guest-core=off,mem- merge=off -cpu host,- hypervisor,hv_time,hv_relaxed,hv_vapic,hv_spinlocks=0x1000 Another thing, I make use of vCPU pinning in my libvirt configuration and I think this would help you as well. The CPUs I use for virtual machines are removed from Linux kernel scheduler, with "isolcpus" option. FWIW my motherboard is SuperMicro X9DA7. And one more thing, when setting up my VMs I took particular care to ensure that the physical cores I pinned my vCPUs to, are all on the same socket and directly attached to PCIe slots that I mapped to my VMs with vfio. B. -- Bronek Kozicki b...@spamcop.net On Thu, 23 Feb 2017, at 11:22 AM, Paige Thompson wrote: > I have been running this setup since October and I have tried since > this time to fix the same issues without any success either in terms > of isolating the problem or fixing it. Here’s a lot of details/specs > about the setup that I could think of off-hand to include: > > https://gist.github.com/cloudkitsch/eefec59233269ace0c9707d0a57e0d5f > > However before diving into that I want to merely point out that the > problem I’m having is not specific to my graphics configuration which > works just fine except that HDMI audio doesn’t work. Not really sure > why, maybe because I’m running Windows 10 N? Don’t know. Seems like I > remember HDMI audio working on my Radeon 5770 / Opteron setup that I > had VFIO setup on quite a while ago. > > I don’t really want HDMI audio either. I have a Yamaha MG10-XU mixer > connected to a USB 3 PCIe card that is also passed through to the > guest. It is a USB audio DAC. The problem I’m having is very > specifically with this mixer however the mixer works just fine on > other computers. It doesn’t matter what buffer size I’m using @ > 44.1khz (lowest sampling rate) I still have the same problem which is > hard to explain because while I can reproduce it consistently I can’t > understand the behavior. Asides from theories, I’m not really sure > where I would start to test. I think that other people around me are > more frustrated with it than I am but I would really like to first > isolate the problem and provide my time (while available) to do what I > can to eliminate the behavior or fix the problem. > > I would like to suggest a few reasons why it might be happening, > starting with the fact that the audio will start to skip when the load > on the bare metal host increases or is saturated. This is not always > the case, but I have not found a way to dedicate specific cores to the > gust without having to do something really backwards with numactl to > ensure nothing ever touches the cores that the guest is using. Maybe > this is not worth trying anyway? It seems to suggest that the USB ASIO > driver for the MG10-XU has issues with timing that are impacted by not > enough CPU cycles. > > It must be more than that though, because it seems to also cut out and > skip relentlessly with mpeg (x264 specifically.) In a lot of games the > sound tends to skip during cinematics and some high bandwidth movies > consistently cause this problem. > > However, I can get audio playback up to 192khz FLAC working but the > driver usually crashes after a while and usually requires the whole > system to be pretty idle. The mixer driver doesn’t crash like that on > other computers. Both the VGA card and USB card are situated in PCIe > slots adjacent to the same CPU in the NUMA topology however I’m not > making any changes to the NUMA configuration at runtime, I tried > without finding that it made any difference. > > I used to have another USB card but that one did the same thing. > Everything else that I could possibly care about works fantastic, > including the mouse responsiveness—I have a whole powered hub of USB > devices including an xBox controller connected to the USB card all of > which work great. Games work really well in 1080p@120hz. I would try > to pass the mixer through VIA USB redirection (same way I’m doing the > corsair PSU) but it wouldn’t work and I don’t imagine it would be much > better. I’ve also tried getting my Scarlett 2i2 with it but I have the > same kind of problems and it typically doesn’t work for more than 20 > seconds at a time. > > Any thoughts or information you have to share would be appreciated. > I’d be happy to try and debug this some more but I’m completely out of > ideas of where to go. It’s an interesting problem to say the least. I > have tried a a lot of different things except those that I can’t > really try. Please get in touch if you have any ideas. > > Thank you, > > -Paige > > _________________________________________________ > vfio-users mailing list > vfio-users@redhat.com > https://www.redhat.com/mailman/listinfo/vfio-users
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