Hi, Gerd. What's your opinion about this issue? Thanks!
Best regards, -Gonglei > -----Original Message----- > From: Gonglei (Arei) > Sent: Wednesday, March 26, 2014 4:15 PM > To: 'Gerd Hoffmann' > Cc: qemu-devel@nongnu.org; Huangweidong (C) > Subject: RE: [PATCH] uhci: Lower uhci timer freq when guest is idle > > > -----Original Message----- > > From: Gerd Hoffmann [mailto:kra...@redhat.com] > > Sent: Wednesday, March 26, 2014 3:59 PM > > To: Gonglei (Arei) > > Cc: qemu-devel@nongnu.org; Huangweidong (C) > > Subject: Re: [PATCH] uhci: Lower uhci timer freq when guest is idle > > > > On Mi, 2014-03-26 at 11:57 +0800, arei.gong...@huawei.com wrote: > > > From: Gonglei <arei.gong...@huawei.com> > > > > > > UHCI emulation polls the device at a freq of 1000HZ, which consumes > > > 12~13% CPU even though a Windows guest is completely idle when the > guest > > > was configed usb1.1 tablet devcie. This solution counts accumulated NAK > > > packets. when it reaches to 64, then the guest is supposed to be idle > > > and the freq is lowered to 10HZ. > > > > > > This patch has been tested on Win7/WinXP/Win2008 guests, that reduces > > > the CPU consume from 12~13% to 6~7%. > > > > Which qemu version did you test with? > I tested it with the latest qemu upstream mainline. > > BTW, I encountered the windows guest boot up failed problem which I have > reported. > > >With any 2.0 release candidate > > windows guests should suspend the usb-tablet. And possibly stop all usb > > polling done by the uhci controller in case the tables is the only > > device connected. > Yeah, if there is no device attached uhci controller, I think we can reduce > the > freq, > otherwise the CPU consume is waste. > > Best regards, > -Gonglei
