[vfio-users] Qemu 2.3 slow

[José Ramón Muñoz Pekkarinen]

	Hi,

	I just did some quick test at this point, and, when not using 
passthrough, in version 2.4.0, everything seems normal and boot the machine 
correctly. When using passthrough, just happens a blinking underscore on a 
black background.

	Latest output from /var/log/messages is this:

Aug 14 19:55:53 koalita sudo[4480]:     root : TTY=pts/1 ; 
PWD=/home/kandalf/machines ; USER=root ; COMMAND=/usr/sbin/vfio-bind 
0000:01:00.0
Aug 14 19:55:53 koalita sudo[4480]: pam_unix(sudo:session): session opened for 
user root by kandalf(uid=0)
Aug 14 19:55:53 koalita kernel: vgaarb: device changed decodes: 
PCI:0000:01:00.0,olddecodes=io+mem,decodes=io+mem:owns=none
Aug 14 19:55:53 koalita sudo[4480]: pam_unix(sudo:session): session closed for 
user root
Aug 14 19:55:53 koalita sudo[4486]:     root : TTY=pts/1 ; 
PWD=/home/kandalf/machines ; USER=root ; COMMAND=/usr/sbin/vfio-bind 
0000:01:00.1
Aug 14 19:55:53 koalita sudo[4486]: pam_unix(sudo:session): session opened for 
user root by kandalf(uid=0)
Aug 14 19:55:53 koalita sudo[4486]: pam_unix(sudo:session): session closed for 
user root
Aug 14 19:55:59 koalita kernel: xhci_hcd 0000:00:10.0: ERROR Transfer event 
TRB DMA ptr not part of current TD ep_index 0 comp_code 1
Aug 14 19:55:59 koalita kernel: xhci_hcd 0000:00:10.0: Looking for event-dma 
000000000001b000 trb-start 000000000001cfe0 trb-end 000000000001d000 seg-start 
000000000001c000 seg-end 000000000001cff0
Aug 14 19:55:59 koalita kernel: vfio-pci 0000:01:00.0: enabling device (0000 -> 
0003)
Aug 14 19:56:03 koalita kernel: xhci_hcd 0000:00:10.0: ERROR Transfer event 
TRB DMA ptr not part of current TD ep_index 0 comp_code 1
Aug 14 19:56:03 koalita kernel: xhci_hcd 0000:00:10.0: Looking for event-dma 
000000000001b000 trb-start 000000000001cfe0 trb-end 000000000001d000 seg-start 
000000000001c000 seg-end 000000000001cff0
Aug 14 19:56:05 koalita kernel: usb 3-5: reset low-speed USB device number 2 
using ohci-pci

	It seems to me like I should give it a try with virtio passthrough, as it 
seems more an error in the input devices. How do you feel about it?

	Thanks!

	José.

On Friday 14 August 2015 07:37:03 Jose Ramon Muñoz Pekkarinen wrote:
> Hi,
> 
> I'm not sure if it's the device, as long as it just shows a black screen
> with a blinking underscore. Some times waiting long some text regarding to
> the boot loader comes. I'll try it with 2.4 using different scenarios and
> come back with the results this evening.
> 
> Thanks Alex!
> 
> José.
> 
> -----Original Message-----
> From: "Alex Williamson" <alex.williamson at redhat.com>
> Sent: ‎13/‎08/‎2015 22:23
> To: "José Ramón Muñoz Pekkarinen" <koalinux at gmail.com>
> Cc: "vfio-users at redhat.com" <vfio-users at redhat.com>
> Subject: Re: [vfio-users] Qemu 2.3 slow
> 
> On Thu, 2015-08-13 at 22:05 +0300, José Ramón Muñoz Pekkarinen wrote:
> > 	Hi,
> > 	
> > 	Do anyone use qemu-2.3 for vfio passthrough? I tried it and it
> > 
> > considerably slowdown the startup of the machine at unusable point, so I
> > don't really know if it's just my setup.
> 
> Unless something is incredibly wrong, like not enabling KVM, the
> performance of an assigned device is fairly well independent of QEMU.
> The whole idea of device assignment is to have as little interaction
> with the hypervisor as possible.  If the slowdown is unrelated to the
> assigned device, you should try QEMU 2.4 and report the issue to the
> QEMU lists.  Thanks,
> 
> Alex