From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juergen Gross Subject: emulated tsc and frequency info Date: Tue, 20 Jul 2010 11:20:37 +0200 Message-ID: <4C456A65.2020100@ts.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org Hi, with xen 4.0 and xen-unstable I see weird tsc information in my HVM-domain with PV-driver, if xen chooses to emulate tsc (d->arch.vtsc is set): In the shared info page the tsc_to_system_mul is still reflecting the host cpu frequency instead of the emulated 1 GHz. The reason is quite simple: tsc_set_info() is never called with a gtsc_khz value other than 0. I wonder which solution is the correct one: - if tsc_set_info() is called with gtsc_khz=0, assume 1 GHz (my favorite). - don't use 0 as default value for gtsc_khz when calling tsc_set_info() (this would require changes in the tools, too). - let the domU check the vtsc-flag in cpuid-info and assume 1 GHz then (very ugly in my opinion). Any thoughts? Juergen -- Juergen Gross Principal Developer Operating Systems TSP ES&S SWE OS6 Telephone: +49 (0) 89 3222 2967 Fujitsu Technology Solutions e-mail: juergen.gross@ts.fujitsu.com Domagkstr. 28 Internet: ts.fujitsu.com D-80807 Muenchen Company details: ts.fujitsu.com/imprint.html