From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC] fix VMX TSC synchronicity Date: Wed, 16 Jan 2008 10:46:11 +0200 Message-ID: <478DC453.1000404@qumranet.com> References: <20080111204933.GA28318@dmt> <478A01D1.7000402@qumranet.com> <20080114160647.GA15919@dmt> <478CC448.1030901@qumranet.com> <478CC819.3040106@csgraf.de> <478CCCA9.2080300@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , Alexander Graf , kvm-devel To: Andi Kleen Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org [fixing gmane emails, urgfhsz] Andi Kleen wrote: > Avi Kivity writes: > > >> Thanks; that's reassuring to know that it will work (at least on Intel). >> > > Actually there are modern Intel systems which still have instable TSCs; > e.g. IBM Summit multi node systems and some others. So you should > still handle that case. > I really don't see any way we could. If the guest assumes tscs are synchronous, and they really are not, there's nothing we can do. [well, we could trap and emulate rdtsc, but performance would tank] You might taskset guests into a single node on such systems, which is a good idea anyway. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/