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?") The last patch is the only one that actually tries to rebalance cpus according to steal time information. For that, I do have some experiments I did here to see if it is working, will try to provide more precise data in the next submission. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
