Re: AIO requests may be disordered by Qemu-kvm iothread with disk cache=writethrough, Bug or Feature?

2015-10-14 Thread Stefan Hajnoczi
On Thu, Oct 08, 2015 at 07:59:56PM +0800, charlie.song wrote: > We recently try to use Linux AIO from guest OS and find that the IOthread > mechanism of Qemu-KVM will reorder I/O requests from guest OS > even when the AIO write requests are issued from a single thread in order. > This does

Re: AIO requests may be disordered by Qemu-kvm iothread with disk cache=writethrough, Bug or Feature?

2015-10-08 Thread Fam Zheng
On Thu, 10/08 19:59, charlie.song wrote: > Dear KVM Developers: > I am Xiang Song from UCloud company. We currently encounter a weird > phenomenon about Qemu-KVM IOthread. > We recently try to use Linux AIO from guest OS and find that the IOthread > mechanism of Qemu-KVM will reorder

Re: Re: AIO requests may be disordered by Qemu-kvm iothread with disk cache=writethrough, Bug or Feature?

2015-10-08 Thread Fam Zheng
On Fri, 10/09 11:25, charlie.song wrote: > At 2015-10-08 23:37:02, "Fam Zheng" wrote: > >On Thu, 10/08 19:59, charlie.song wrote: > >> Dear KVM Developers: > >> I am Xiang Song from UCloud company. We currently encounter a weird > >> phenomenon about Qemu-KVM IOthread. >

Re: Re: AIO requests may be disordered by Qemu-kvm iothread with disk cache=writethrough, Bug or Feature?

2015-10-08 Thread charlie.song
At 2015-10-08 23:37:02, "Fam Zheng" wrote: >On Thu, 10/08 19:59, charlie.song wrote: >> Dear KVM Developers: >> I am Xiang Song from UCloud company. We currently encounter a weird >> phenomenon about Qemu-KVM IOthread. >> We recently try to use Linux AIO from guest OS

Re: Re: Re: AIO requests may be disordered by Qemu-kvm iothread with disk cache=writethrough, Bug or Feature?

2015-10-08 Thread charlie.song
At 2015-10-09 12:33:20, "charlie.song" wrote: >At 2015-10-09 12:16:03, "Fam Zheng" wrote: >>On Fri, 10/09 11:25, charlie.song wrote: >>> At 2015-10-08 23:37:02, "Fam Zheng" wrote: >>> >On Thu, 10/08 19:59, charlie.song wrote: >>> >> Dear

Re: Re: Re: AIO requests may be disordered by Qemu-kvm iothread with disk cache=writethrough, Bug or Feature?

2015-10-08 Thread charlie.song
At 2015-10-09 12:16:03, "Fam Zheng" wrote: >On Fri, 10/09 11:25, charlie.song wrote: >> At 2015-10-08 23:37:02, "Fam Zheng" wrote: >> >On Thu, 10/08 19:59, charlie.song wrote: >> >> Dear KVM Developers: >> >> I am Xiang Song from UCloud company. We