From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Bader Subject: Workings/effectiveness of the xen-acpi-processor driver Date: Wed, 25 Apr 2012 15:00:58 +0200 Message-ID: <4F97F58A.8090409@canonical.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============2199221830262411281==" Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "xen-devel@lists.xensource.com" Cc: Jan Beulich , Konrad Rzeszutek Wilk List-Id: xen-devel@lists.xenproject.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --===============2199221830262411281== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="------------enigCE74410632203E6E18255326" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigCE74410632203E6E18255326 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Since there have been requests about that driver to get backported into 3= =2E2, I was interested to find out what or how much would be gained by that. The first system I tried was an AMD based one (8 core Opteron 6128@2GHz).= Which was not very successful as the drivers bail out of the init function beca= use the first call to acpi_processor_register_performance() returns -ENODEV. Ther= e is some frequency scaling when running without Xen, so I need to do some mor= e debugging there. The second system was an Intel one (4 core i7 920@2.67GHz) which was successfully loading the driver. Via xenpm I can see the various frequenc= ies and also see them being changed. However the cpuidle data out of xenpm looks = a bit odd: #> xenpm get-cpuidle-states 0 Max C-state: C7 cpu id : 0 total C-states : 2 idle time(ms) : 10819311 C0 : transition [00000000000000000001] residency [00000000000000005398 ms] C1 : transition [00000000000000000001] residency [00000000000010819311 ms] pc3 : [00000000000000000000 ms] pc6 : [00000000000000000000 ms] pc7 : [00000000000000000000 ms] cc3 : [00000000000000000000 ms] cc6 : [00000000000000000000 ms] Also gathering samples over 30s does look like only C0 and C1 are used. T= his might be because C1E support is enabled in BIOS but when looking at the intel_idle data in sysfs when running without a hypervisor will show C3 a= nd C6 for the cores. That could have been just a wrong output, so I plugged in = a power meter and compared a kernel running natively and running as dom0 (with an= d without the acpi-processor driver). Native: 175W dom0: 183W (with only marginal difference between with or without the processor driver) [yes, the system has a somewhat high base consumption which I attribute t= o a ridiculously dimensioned graphics subsystem to be running a text console]= This I would take as C3 and C6 really not being used and the frequency sc= aling having no impact on the idle system is not that much surprising. But if t= hat was true it would also limit the usefulness of the turbo mode which I underst= and would also be limited by the c-state of the other cores. Do I misread the data I see? Or maybe its a known limitation? In case it = is worth doing more research I'll gladly try things and gather more data. Thanks, Stefan --------------enigCE74410632203E6E18255326 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQIcBAEBCgAGBQJPl/WKAAoJEOhnXe7L7s6j4U4QAK7qNx2TVnRLPA7CLQs+QqJ2 wG1b8kBvK9k0npqsoLNK5uE6tNW3w5JFvt3eD+3K+YBQ3Pw82LnETQz2w3Cuz/pU Psu+WPIZmaKq/pwVUYC9ZK7IjuGK8RIW03nkBN3klmbR8xQgP+B2AG7i4VF5G//h Nz16CwuM0BwU/QHgjJBF0Z0MkzX0b94RBoeumuXq9C97TQJoqFkEEbSr/4dxKJLu h6qqhXuZbK164qXTgMfsYrQeBUI7pK2WC5w8P6ikEanXmtVtm8gd70KBjwIilmyz nVcWVOypMLjJCa3zgydZ9h9PnRzyPtjwi/BorLtM3g5mmtmzqcod4MKrb0R+Nv15 XPWYJRRadyTGZ42tSbWACt6QztzxwBly6kowQ9Y98lM6NedzkZtQcArV26mfn7L3 JogyGjesguqH+Npy3XpIKyeslozHIoC6rANje62diP3ExatTdhPvHzHRq9UqVRyU NqOFEulBCdua3+ZTyoMFRKFjUDebl2uNHXjkrw35W3+FWnqu8pYJCqygvTleIzVe A4Nh9s4o+KVZYlZ+aY9thoZiQcSZWQR33Gu+UUDaMqZ1DzklHB/KXUF+KMwg/pNe N37fg2Q2JRLcSvlyb6EsfNt3Rnl6qHk7eT1Lo3q1N8gqFga7epL/f9JgJzwUG3ov hGXSR7B6j5j6ZzaMGMGr =X8Qg -----END PGP SIGNATURE----- --------------enigCE74410632203E6E18255326-- --===============2199221830262411281== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel --===============2199221830262411281==--