On Wed, 2013-03-06 at 14:34 +0100, Frederic Weisbecker wrote: > 2013/3/5 Michael Wolf <mjw@xxxxxxxxxxxxxxxxxx>: > > Sorry for the delay in the response. I did not see the email > > right away. > > > > On Mon, 2013-02-18 at 22:11 -0300, Marcelo Tosatti wrote: > >> On Mon, Feb 18, 2013 at 05:43:47PM +0100, Frederic Weisbecker wrote: > >> > 2013/2/5 Michael Wolf <mjw@xxxxxxxxxxxxxxxxxx>: > >> > > In the case of where you have a system that is running in a > >> > > capped or overcommitted environment the user may see steal time > >> > > being reported in accounting tools such as top or vmstat. This can > >> > > cause confusion for the end user. > >> > > >> > Sorry, I'm no expert in this area. But I don't really understand what > >> > is confusing for the end user here. > >> > >> I suppose that what is wanted is to subtract stolen time due to 'known > >> reasons' from steal time reporting. 'Known reasons' being, for example, > >> hard caps. So a vcpu executing instructions with no halt, but limited to > >> 80% of available bandwidth, would not have 20% of stolen time reported. > > > > Yes exactly and the end user many times did not set up the guest and is > > not aware of the capping. The end user is only aware of the performance > > level that they were told they would get with the guest. > > > >> > >> But yes, a description of the scenario that is being dealt with, with > >> details, is important. > > > > I will add more detail to the description next time I submit the > > patches. How about something like,"In a cloud environment the user of a > > kvm guest is not aware of the underlying hardware or how many other > > guests are running on it. The end user is only aware of a level of > > performance that they should see." or does that just muddy the picture > > more?? > > That alone is probably not enough. But yeah, make sure you clearly > state the difference between expected (caps, sched bandwidth...) and > unexpected (overcommitting, competing load...) stolen time. Then add a > practical example as you made above that explains why it matters to > make that distinction and why you want to report it. > Ok, I understand what you are requesting. I will make sure to add it to the description the next time I submit the patches. -- 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
