[vfio-users] Disk Performance

Bob Dawes xochipilli4 at yahoo.com
Sun Apr 3 09:34:22 UTC 2016

My apologies as you appear to have inherited all my unnecessary 
configuration options on the block device. As I'm messing around with 
qemu and I don't really understand that driver yet I tend to explicitly 
set every option so next time I use the VM with a new testing version of 
qemu my VM doesn't do unpredictable things because some feature I'm not 
messing with got switched on or off.

You may prefer to always have the author's best settings which in the 
general case is usually advisable and is achieved by leaving parameters 
implicit. For your config this would be:

-object iothread,id=iothread2 \
-device virtio-blk-pci,drive=ssd2,iothread=iothread2

Naturally, you will find most authors tend to be cautious about 
switching on experimental or risky features, so to test those you 
usually have to explicitly set parameters. You can type 'info qtree' in 
the qemu console and check the configs parameters if you are interested 
in the fine details, but I wouldn't explicitly set the parameters unless 
you know you need something.

On 03/04/16 03:26, Nick Sarnie wrote:
> Hi,
> Thanks for your detailed post. I believe I have already changed my 
> script to make sense, thanks to the previous reply. I've attached it 
> again below. For networking, I am using a wireless card where I cannot 
> create a bridge, and my IP changes very often. Is there a simple way 
> to manually create a tap with this? I wasn't able to get either of the 
> 2 most popular tutorials working.
> Thanks,
> sarnex
> #!/bin/sh
> export QEMU_AUDIO_DRV=pa
> qemu-system-x86_64 -enable-kvm \
> -m 5120 \
> -cpu host \
> -smp 6,sockets=1,cores=6,threads=1 \
> -device vfio-pci,host=01:00.0,x-vga=on,multifunction=on \
> -device vfio-pci,host=01:00.1 \
> -vga none \
> -device vfio-pci,host=00:12.0 \
> -device vfio-pci,host=00:12.2 \
> -device vfio-pci,host=00:16.0 \
> -device vfio-pci,host=00:16.2 \
> -soundhw ac97 \
> -rtc base=localtime \
> -netdev user,id=net0 \
> -device virtio-net-pci,netdev=net0 \
> -drive 
> if=none,format=raw,cache=none,cache.direct=on,file=/media/500GB/win10.img,aio=native,id=ssd2,discard=off,detect-zeroes=off 
> \
> -object iothread,id=iothread2 \
> -device virtio-

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