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 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 20/07/2010 10:20, "Juergen Gross" <juergen.gross@ts.fujitsu.com> wrote:> 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).That sounds best to me. Cc''ing Dan as he may have an opinion. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 07/20/2010 12:00 PM, Keir Fraser wrote:> On 20/07/2010 10:20, "Juergen Gross"<juergen.gross@ts.fujitsu.com> wrote: > >> 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):correction: only xen 4.0 is affected! xen-unstable does the scaling correctly.>> >> 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). > > That sounds best to me. Cc''ing Dan as he may have an opinion. > > -- Keir > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel > >-- 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 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 20/07/2010 12:52, "Juergen Gross" <juergen.gross@ts.fujitsu.com> wrote:>>> 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): > > correction: only xen 4.0 is affected! > xen-unstable does the scaling correctly.Is it still a problem with the latest 4.0.1 RC (or tip of xen-4.0-testing)? -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 07/20/2010 02:28 PM, Keir Fraser wrote:> On 20/07/2010 12:52, "Juergen Gross"<juergen.gross@ts.fujitsu.com> wrote: > >>>> 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): >> >> correction: only xen 4.0 is affected! >> xen-unstable does the scaling correctly. > > Is it still a problem with the latest 4.0.1 RC (or tip of xen-4.0-testing)?Looking at hvm_get_guest_tsc() it should be okay, too. Sorry for the noise :-( 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 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel