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From: "Zhang, Tina" <tina.zhang@intel.com>
To: "kraxel@redhat.com" <kraxel@redhat.com>,
	"Tian, Kevin" <kevin.tian@intel.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Yuan, Hang" <hang.yuan@intel.com>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"Lv, Zhiyuan" <zhiyuan.lv@intel.com>,
	"intel-gvt-dev@lists.freedesktop.org" 
	<intel-gvt-dev@lists.freedesktop.org>
Subject: RE: [PATCH v5 0/6] Deliver vGPU display refresh event to userspace
Date: Tue, 17 Sep 2019 09:27:08 +0000
Message-ID: <237F54289DF84E4997F34151298ABEBC87734BB6@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <20190905074857.n3akutnoarnfvg4y@sirius.home.kraxel.org>



> -----Original Message-----
> From: intel-gvt-dev [mailto:intel-gvt-dev-bounces@lists.freedesktop.org] On
> Behalf Of kraxel@redhat.com
> Sent: Thursday, September 5, 2019 3:49 PM
> To: Zhang, Tina <tina.zhang@intel.com>
> Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org; Yuan, Hang
> <hang.yuan@intel.com>; alex.williamson@redhat.com; Lv, Zhiyuan
> <zhiyuan.lv@intel.com>; intel-gvt-dev@lists.freedesktop.org
> Subject: Re: [PATCH v5 0/6] Deliver vGPU display refresh event to userspace
> 
>   Hi,
> 
> > Option 2: QEMU provides the emulated display refresh event to the
> > vgpus provided by vendor driver. For vgpus, the display refresh event
> > can be considered as the vblank event which is leveraged by guest
> > window manager to do the plane update or mode-setting.
> 
> > People are asking if option 2 could be a better choice.
> 
> Certainly worth trying, maybe it even makes sense to implement both and
> let qemu pick one, possibly even switch them at runtime.
> 
> qemu can change the refresh rate.  vnc and sdl use that to reduce the
> refresh rate in case nobody is looking (no vnc client connected, sdl window
> minimized).  It surely makes sense to make that visible to the guest so it can
> throttle display updates too.  I'm not sure vblank is the way to go though,
> guests might run into vblank irq timeouts in case the refresh rate is very
> low ...

Indeed, low vblank rate isn't expected by guest gfx driver. It complains about the timeout error all the time, when the vblank is low. 

Currently, gvt-g provides full virtualized display model (a.k.a. not pv). And the option 2 is more like a pv solution for performance optimization, which is of course a very good proposal. Since the two options have no dependency, this patch-set limits its scope to only include option 1. Thanks.


BR,
Tina

> 
> cheers,
>   Gerd
> 
> _______________________________________________
> intel-gvt-dev mailing list
> intel-gvt-dev@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev

      reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16  2:35 Tina Zhang
2019-08-16  2:35 ` [PATCH v5 1/6] vfio: Define device specific irq type capability Tina Zhang
2019-08-16 20:51   ` Alex Williamson
2019-08-20  0:56     ` Zhang, Tina
2019-08-16  2:35 ` [PATCH v5 2/6] vfio: Introduce vGPU display irq type Tina Zhang
2019-08-16 20:51   ` Alex Williamson
2019-08-20  2:12     ` Zhang, Tina
2019-08-20  7:20       ` kraxel
2019-08-20 15:03         ` Alex Williamson
2019-08-20 15:32       ` Alex Williamson
2019-08-16  2:35 ` [PATCH v5 3/6] drm/i915/gvt: Register vGPU display event irq Tina Zhang
2019-08-16  2:35 ` [PATCH v5 4/6] drm/i915/gvt: Deliver vGPU refresh event to userspace Tina Zhang
2019-08-26  7:55   ` Zhenyu Wang
2019-08-28  1:49     ` Tian, Kevin
2019-08-28  6:59       ` Zhang, Tina
2019-08-28  7:10         ` Tian, Kevin
2019-08-28  7:39           ` Zhang, Tina
2019-08-16  2:35 ` [PATCH v5 5/6] drm/i915/gvt: Deliver async primary plane page flip events at vblank Tina Zhang
2019-08-16  2:35 ` [PATCH v5 6/6] drm/i915/gvt: Add cursor plane reg update trap emulation handler Tina Zhang
2019-09-03  1:26 ` [PATCH v5 0/6] Deliver vGPU display refresh event to userspace Zhang, Tina
2019-09-03  7:43   ` Tian, Kevin
2019-09-05  7:48   ` kraxel
2019-09-17  9:27     ` Zhang, Tina [this message]

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