From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:53502) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RzNsB-0000HB-QB for qemu-devel@nongnu.org; Mon, 20 Feb 2012 02:41:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RzNsA-0002NA-N5 for qemu-devel@nongnu.org; Mon, 20 Feb 2012 02:41:23 -0500 Received: from mail-ee0-f45.google.com ([74.125.83.45]:63552) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RzNsA-0002N5-FF for qemu-devel@nongnu.org; Mon, 20 Feb 2012 02:41:22 -0500 Received: by eekd17 with SMTP id d17so2350373eek.4 for ; Sun, 19 Feb 2012 23:41:21 -0800 (PST) Sender: Paolo Bonzini Message-ID: <4F41F91F.7060206@redhat.com> Date: Mon, 20 Feb 2012 08:41:19 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 0/4] RTC: New logic to emulate RTC List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Zhang, Yang Z" Cc: "aliguori@us.ibm.com" , Marcelo Tosatti , Jan Kiszka , "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" On 02/20/2012 01:24 AM, Zhang, Yang Z wrote: > Changes in v2: > Add UIP check logic. > Add logic that next second tick will occur in exactly 500ms later after setting the clock > > Current RTC emulation uses periodic timer(2 timers per second) to update RTC clock. And it will stop CPU staying at deep C-state for long period. Our experience shows the Pkg C6 residency reduced 6% when running 64 idle guest. > The following patch stop the two periodic timer and only updating RTC clock when guest try to read it. > > --- > Yang Zhang (4): > RTC: Update the RTC clock only when reading it > RTC: Add RTC update-ended interrupt support > RTC: Add alarm support > RTC: Add UIP(update in progress) check logic > > hw/mc146818rtc.c | 447 +++++++++++++++++++++++++++++++++++++----------------- > 1 files changed, 308 insertions(+), 139 deletions(-) > > best regards > yang > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Thanks, this looks much better! I'll run it through some tests. We also should try to keep migration working from older versions using the load_old callback. Paolo