From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH v2 0/4] RTC: New logic to emulate RTC Date: Mon, 20 Feb 2012 08:41:19 +0100 Message-ID: <4F41F91F.7060206@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "qemu-devel@nongnu.org" , Jan Kiszka , "kvm@vger.kernel.org" , "aliguori@us.ibm.com" , Marcelo Tosatti To: "Zhang, Yang Z" Return-path: Received: from mail-ee0-f46.google.com ([74.125.83.46]:51040 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751995Ab2BTHlW (ORCPT ); Mon, 20 Feb 2012 02:41:22 -0500 Received: by eekc14 with SMTP id c14so2129435eek.19 for ; Sun, 19 Feb 2012 23:41:21 -0800 (PST) In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: 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