From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Vivier Subject: Re: [PATCH 0/4] Virtual Machine Time Accounting Date: Mon, 20 Aug 2007 16:39:39 +0200 Message-ID: <46C9A7AB.1030003@bull.net> References: <46C99371.7070705@bull.net> <18121.39541.790665.686081@stoffel.org> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1613340631==" Cc: kvm-devel , linux-kernel , virtualization To: John Stoffel Return-path: In-Reply-To: <18121.39541.790665.686081-HgN6juyGXH5AfugRpC6u6w@public.gmane.org> 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 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --===============1613340631== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig7C4697859CD76F6581AFFD24" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig7C4697859CD76F6581AFFD24 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi John, John Stoffel wrote: >=20 > Laurent> The aim of these four patches is to introduce Virtual Machine > Laurent> time accounting. >=20 > So what does this buy us? What increased functionality? =20 >=20 functionnalities: - allow to measure time spent by a CPU in a virtual CPU. - allow to display in /proc/state this value by CPU - allow to display in /proc//state this value by process - allow KVM to use these 3 previous functionnalities > Laurent> [PATCH 1/4] as recent CPUs introduce a third running state, > Laurent> after "user" and "system", we need a new field, "guest", in > Laurent> cpustat to store the time used by the CPU to run virtual > Laurent> CPU. Modify /proc/stat to display this new field. >=20 > What happens when you have multiple guests, is this state cummulative? = =20 Yes, like system time and user time are. > I've glanced over these patches and the #ifdefs are ugly..., esp since #ifdefs are ugly, I agree... I can remove them. But "#ifdef" allows to save space and time (and it is not a beauty show).= > the overhead seems to exist even if you don't run any Guest CPUs. Or > whatever you're doing here. Can you explain ? > Please justify this patch more in terms of what it provides and why > it's a good thing to have. =20 Well... it provides the time spent by CPUs in virtual CPUs. It is usefull only if you run Virtual Machine on your host (like KVM, lgu= est, kqemu...) to know how many time your CPUs dedicate to virtual machine exe= cution. It's a good thing to have like user time and system time are good things = to have... do you use 'top' or 'time' sometime ? Laurent --=20 ------------- Laurent.Vivier-6ktuUTfB/bM@public.gmane.org -------------- "Software is hard" - Donald Knuth --------------enig7C4697859CD76F6581AFFD24 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.7 (GNU/Linux) iD8DBQFGyaeu9Kffa9pFVzwRAqydAKCSG136gnCONpBpMj0/gsaNEcAsJACgjSd4 HVdzGjIUyh0DKiOBnidtZjU= =vVLG -----END PGP SIGNATURE----- --------------enig7C4697859CD76F6581AFFD24-- --===============1613340631== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ --===============1613340631== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ kvm-devel mailing list kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org https://lists.sourceforge.net/lists/listinfo/kvm-devel --===============1613340631==--