> -----Original Message----- > From: intel-gvt-dev [mailto:intel-gvt-dev-bounces@xxxxxxxxxxxxxxxxxxxxx] On > Behalf Of kraxel@xxxxxxxxxx > Sent: Thursday, September 5, 2019 3:49 PM > To: Zhang, Tina <tina.zhang@xxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Yuan, Hang > <hang.yuan@xxxxxxxxx>; alex.williamson@xxxxxxxxxx; Lv, Zhiyuan > <zhiyuan.lv@xxxxxxxxx>; intel-gvt-dev@xxxxxxxxxxxxxxxxxxxxx > 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@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev
