Re: [Qemu-devel] [PATCH 2/3] Improve xen_disk response latency

2018-11-02 Thread Anthony PERARD
On Fri, Nov 02, 2018 at 10:01:04AM +, Tim Smith wrote: > If the I/O ring is full, the guest cannot send any more requests > until some responses are sent. Only sending all available responses > just before checking for new work does not leave much time for the > guest to supply new work, so thi

Re: [Qemu-devel] [PATCH 2/3] Improve xen_disk response latency

2018-11-02 Thread Paul Durrant
> -Original Message- > From: Tim Smith [mailto:tim.sm...@citrix.com] > Sent: 02 November 2018 10:01 > To: xen-de...@lists.xenproject.org; qemu-devel@nongnu.org; qemu- > bl...@nongnu.org > Cc: Anthony Perard ; Kevin Wolf > ; Paul Durrant ; Stefano > Stabellini ; Max Reitz > Subject: [PATC

[Qemu-devel] [PATCH 2/3] Improve xen_disk response latency

2018-11-02 Thread Tim Smith
If the I/O ring is full, the guest cannot send any more requests until some responses are sent. Only sending all available responses just before checking for new work does not leave much time for the guest to supply new work, so this will cause stalls if the ring gets full. Also, not completing rea

[Qemu-devel] [PATCH 2/3] Improve xen_disk response latency

2018-11-02 Thread Tim Smith
If the I/O ring is full, the guest cannot send any more requests until some responses are sent. Only sending all available responses just before checking for new work does not leave much time for the guest to supply new work, so this will cause stalls if the ring gets full. Also, not completing rea

Re: [Qemu-devel] [PATCH 2/3] Improve xen_disk response latency

2018-09-07 Thread Paul Durrant
> -Original Message- > From: Qemu-devel [mailto:qemu-devel- > bounces+paul.durrant=citrix@nongnu.org] On Behalf Of Tim Smith > Sent: 07 September 2018 11:21 > To: qemu-devel@nongnu.org > Subject: [Qemu-devel] [PATCH 2/3] Improve xen_disk response latency > >

[Qemu-devel] [PATCH 2/3] Improve xen_disk response latency

2018-09-07 Thread Tim Smith
If the I/O ring is full, the guest cannot send any more requests until some responses are sent. Only sending all available responses just before checking for new work does not leave much time for the guest to supply new work, so this will cause stalls if the ring gets full. Also, not completing rea