From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39986) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fntvX-0006fp-H5 for qemu-devel@nongnu.org; Thu, 09 Aug 2018 19:01:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fntvU-00074o-HG for qemu-devel@nongnu.org; Thu, 09 Aug 2018 19:01:07 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:49830 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fntvU-00074W-Av for qemu-devel@nongnu.org; Thu, 09 Aug 2018 19:01:04 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A3C9C819700A for ; Thu, 9 Aug 2018 23:01:03 +0000 (UTC) Date: Fri, 10 Aug 2018 02:01:00 +0300 From: "Michael S. Tsirkin" Message-ID: <20180810015952-mutt-send-email-mst@kernel.org> References: <1533741349-199141-1-git-send-email-imammedo@redhat.com> <1533741349-199141-4-git-send-email-imammedo@redhat.com> <20180808231636-mutt-send-email-mst@kernel.org> <20180809120011.51023bf2@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180809120011.51023bf2@redhat.com> Subject: Re: [Qemu-devel] [RFC PATCH 3/4] pc: acpi: add _CST support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: qemu-devel@nongnu.org On Thu, Aug 09, 2018 at 12:00:11PM +0200, Igor Mammedov wrote: > On Wed, 8 Aug 2018 23:17:48 +0300 > "Michael S. Tsirkin" wrote: > > > On Wed, Aug 08, 2018 at 05:15:48PM +0200, Igor Mammedov wrote: > > > Reuse CPU hotplug IO registers for passing a CST entry > > > containing package for shalowest C1 using mwait and > > > read it out in guest with new CCST AML method. > > > > I don't see how 1 entry is enough. We need to describe full _CST package so > > that guest can do reasonable power management on the CPU. > I was assuming that CST are to be used for mwait/monitor idle combo > to help reduce latencies/vmexits on cpus wakeup from idle state, hence 1 entry. > It's trivial to add as much as needed entries though. > If you are fine with approach I can respin patch with arbitrary > number of CStates. You will find that the code then becomes very messy, and dynamic size of the package is one of the things that makes it messy. > > > The CState support is optional and could be turned on > > > with '-global PIIX4_PM.cstate=on' CLI option. > > > > > > Signed-off-by: Igor Mammedov > > > --- > [...]