Messages in this thread | | | Date | Mon, 13 Aug 2007 16:22:50 +0200 | From | Laurent Vivier <> | Subject | Re: [kvm-devel] [PATCH 0/2][KVM] guest time accounting |
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Christian Borntraeger wrote: > Am Freitag, 10. August 2007 schrieb Laurent Vivier: >> 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 > 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. >
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 the accounting functions.
Laurent -- ------------- Laurent.Vivier@bull.net -------------- "Software is hard" - Donald Knuth
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