`On Tue, Nov 21, 2017 at 09:07:14AM -0800, Andi Kleen wrote:> On Tue, Nov 21, 2017 at 10:28:06AM +0100, Jiri Olsa wrote:> > On Mon, Nov 20, 2017 at 08:03:06AM -0800, Andi Kleen wrote:> > > > > Yes it is.> > > > > > > > > > It's for the complete sampling period because it is computed> > > > > over the delta from the last sample to the previous sample.> > > > > > > > > > There isn't really a metric at a point, it is always over a interval.> > > > > > > > agreed, it's the count we meassured from the last sample.. but the> > > > 'averaged' word above implies to me we compute some average over the> > > > 'sampling' period, which we dont do> > > > > > Do you have a better word in mind?> > > > > > AFAIK average is the right word for this because it's the summary> > > for that time period.> > > > the way I understand it is that we take the values from the current> > sample and count the metric value.. so the phrase:> > > > .. the metric computed is averaged over the whole sampling period,> > not just for the sample point ...> > > > does not make sense to me.. because we take the value of that> > single 'sample point'.. I dont see any average sum in there> > The current samples contains the sum of event counts for a sampling period.> > EventA-1           EventA-2                EventA-3      EventA-4> EventB-1     EventB-2                             EventC-3       > >                          gap with no events                overflow> |-----------------------------------------------------------------|> period-start                                             period-end> ^                                                                 ^> |                                                                 |> previous sample                                      current sample> > > So EventA = 4 and EventB = 3 at the sample point> > I generate a metric, let's say EventA / EventB. It applies> to the whole period.> > But the metric is over a longer time which does not have the same> behavior. For example the gap above doesn't have any events, while> they are clustered at the beginning and end of the sample period.> > But we're summing everything together. The metric doesn't know> that the gap is different than the busy period. > > That's what I'm trying to express with averaging.I see, so averaging to express the sum of the uneven distributionof the counts.. ookthanks for bearing with me ;-)jirka`