Messages in this thread | | | Date | Wed, 02 Feb 2011 12:51:17 +0200 | From | Avi Kivity <> | Subject | Re: [PATCH v2 3/6] KVM-GST: KVM Steal time accounting |
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On 02/02/2011 12:11 PM, Avi Kivity wrote: > On 02/01/2011 05:57 PM, Glauber Costa wrote: >> On Sun, 2011-01-30 at 16:04 +0200, Avi Kivity wrote: >> > On 01/28/2011 09:52 PM, Glauber Costa wrote: >> > > This patch accounts steal time time in kernel/sched. >> > > I kept it from last proposal, because I still see advantages >> > > in it: Doing it here will give us easier access from scheduler >> > > variables such as the cpu rq. The next patch shows an example of >> > > usage for it. >> > > >> > > Since functions like account_idle_time() can be called from >> > > multiple places, not only account_process_tick(), steal time >> > > grabbing is repeated in each account function separatedely. >> > > >> > >> > I accept that steal time is worthwhile, but do you have some way to >> > demonstrate that the implementation actually works and is beneficial? >> > >> > Perhaps run two cpu-bound compute processes on one vcpu, >> overcommit that >> > vcpu, and see what happens to the processing rate with and without >> steal >> > time accounting. I'd expect a fairer response with steal time >> accounting. >> >> Avi, >> >> There are two things here: >> One of them, which is solely the accounting of steal time, (patches 1 to >> 4) has absolutely nothing to do with what you said. Its sole purpose is >> to provide the user with information about "why is my process slow if I >> am using 100 % of my cpu?") > > Right. Like irq and softirq time, we need to report this to the user, > as it's potentially much higher.
Of course, it's not enough to just account for this time, you also have to expose it somewhere, and update tools like top(1) to display it.
-- error compiling committee.c: too many arguments to function
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