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    SubjectRe: [RFC PATCH] LTTng relay buffer allocation, read, write
    * Martin Bligh ( wrote:
    > On Tue, Sep 30, 2008 at 10:22 AM, Martin Bligh <> wrote:
    > >> A 4 byte dataless payload is useless anyway.
    > >
    > > Not at all convinced that's true - we used it for lots of things.
    > > Start and end of irq event is one frequent example.
    > >
    > > Also, in a compact mode, we can record start and end of
    > > syscalls like this (without parameters).
    > Ah, sorry, maybe I misread this. No data with no event ids, etc
    > is fairly useless. 4 bytes data including space to record event ids is OK.

    In Steven's scheme, the event IDs in the 4 bytes are reserved for
    (useless) internal use ;) They can therefore not be used for specific
    tracer event IDs, which I think is a misuse of the precious bits
    otherwise available to store really useful event IDs.


    Mathieu Desnoyers
    OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68

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