From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Vivier Subject: Re: [PATCH 0/2][KVM] guest time accounting Date: Mon, 13 Aug 2007 16:41:29 +0200 Message-ID: <46C06D99.2030106@bull.net> References: <46BC8B39.6050202@bull.net> <200708131605.40479.borntraeger@de.ibm.com> <46C0693A.1080900@bull.net> <46C06AFE.2050702@qumranet.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0663492717==" Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Christian Borntraeger , linux-kernel To: Avi Kivity Return-path: In-Reply-To: <46C06AFE.2050702-atKUWr5tajBWk0Htik3J/w@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) --===============0663492717== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigDDA632D6E8F506DAF2ED56AF" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigDDA632D6E8F506DAF2ED56AF Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Avi Kivity wrote: > Laurent Vivier wrote: >> Christian Borntraeger wrote: >> =20 >>> Am Freitag, 10. August 2007 schrieb Laurent Vivier: >>> =20 >>>> The aim of these two patches is to measure the CPU time used by a >>>> virtual >>>> machine. All comments are welcome... I'm not sure it's the good way >>>> to do =20 >>> that. >>> >>> I did something similar for or s390guest prototype, that Carsten >>> posted in May. I decided to account guest time to the user process >>> instead of adding a new field to avoid hazzle with old top. As you >>> can read in the patch comment, I personally prefer a new field if we >>> can get one. >>> >>> My implementation uses a similar mechanism like hard and softirq. So >>> I have an sie_enter an sie_exit and a task_is_in_sie function - like >>> irq_enter and irq_exit. The main difference is based on the fact, >>> that s390 has precise accouting for irq, steal, user and system time,= >>> and therefore my patch is based on architecture specifc code using >>> CONFIG_VIRT_CPU_ACCOUNT. >>> In general my patch has the same idea as your patch, so I am going to= >>> review your patch and see if it would fit for s390. >>> >>> For reference this is the (never posted) old patch for our >>> virtualisation prototype. It wont work with kvm but it gives you the >>> idea what we had in mind on s390. >>> >>> =20 >> >> thank you for your comment. >> >> As virtualization becomes very popular, perhaps we should implement >> something >> which could be used by all linux supported architectures ? >> (yes, I know it's non-sense for archs like m68k...) >> But my [PATCH 1/2] can be a good start (adding "guest" in cpustat) >> As guest accounting is hw dependent, I think we should add a hook in t= he >> accounting functions. >> =20 >=20 > Isn't PF_VM exactly such a hook? All the hypervisor needs to do is to > set/unset it correctly? In fact, no. PF_VM is used to know we have entered a virtual CPU (the hypervisor set i= t, the scheduler unset it on accounting) I mean a hook in account_system_time() to call a function arch-dependent = to compute the guest time (and modify the system/user time accordingly) if n= eeded. If fact what I find annoying in my patch is it adds to guest time and use= r time some system time. Perhaps you could have a look to the second patch I sen= t. Regards, Laurent --=20 ------------- Laurent.Vivier-6ktuUTfB/bM@public.gmane.org -------------- "Software is hard" - Donald Knuth --------------enigDDA632D6E8F506DAF2ED56AF 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) iD8DBQFGwG2c9Kffa9pFVzwRAhszAKCRtjWfiq6ZYeIel1BQrkaH2IgATACgmdIK 7iMzG7gxu19UXJc7jrn/4mg= =Qs8g -----END PGP SIGNATURE----- --------------enigDDA632D6E8F506DAF2ED56AF-- --===============0663492717== 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. 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