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    SubjectRe: [PATCH v6 1/3] perf/core: use rb trees for pinned/flexible groups
    On Mon, Aug 07, 2017 at 07:27:30PM +0300, Alexey Budankov wrote:
    > On 07.08.2017 18:55, Peter Zijlstra wrote:

    > > In the extreme, if you construct your program such that you'll never get
    > > hit by the tick (this used to be a popular measure to hide yourself from
    > > time accounting)
    >
    > Well, some weird thing for me. Never run longer than one tick?
    > I could imaging some I/O bound code that would fast serve some short
    > messages, all the other time waiting for incoming requests.
    > Not sure if CPU events monitoring is helpful in this case.

    Like I said, in extreme. Typically its less weird.

    Another example is scheduling a very constrained counter/group along
    with a bunch of simple events such that the group will only succeed to
    schedule when its the first. In this case it will get only 1/nr_events
    time with RR, as opposed to the other/simple events that will get
    nr_counters/nr_events time.

    By making it runtime based, the constrained thing will more often be
    head of list and acquire equal total runtime to the other events.

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