From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: RE: cpufreq status information Date: Mon, 08 Sep 2008 15:23:54 +0100 Message-ID: <48C5519A.76E4.0078.0@novell.com> References: <48C540DC.76E4.0078.0@novell.com> <48C545B4.76E4.0078.0@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Kevin Tian Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org >>> "Tian, Kevin" 08.09.08 15:50 >>> >>From: Jan Beulich [mailto:jbeulich@novell.com]=20 >>How? I can't see where the current frequency a CPU is running at >>is being exposed. > >common/sysctl.c: XEN_SYSCTL_get_pmstat Ah, okay, I missed that. But - I can't use this from the kernel anyway, and tools that track the frequency (i.e. KDE sysguard) would need to be modified in order to make use of this. I'd really prefer /proc/cpuinfo to correctly reflect this at least in Dom0. And even beyond that - I can't seem to find any users of the APIs in tools/libxc/xc_pm.c, so these really appear to be dead stubs. >Then you have to pin dom0 vCPU to corresponding pCPU, and have >dom0 with same number as pCPU. I don't think such limitation >necessary for just retrieving some pCPU information. > >Or if you still enable vcpu migration, you have to fake virtual freq >change notification within dom0 at vcpu migration as pCPU may=20 >scale its own freq individually. Why? All I care about is a snapshot value. It doesn't matter whether it's stale by the time I get it, there's nothing going to be calculated from it, apart from statistics. Jan