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    SubjectRe: [PATCH] tracing/markers: make markers select tracepoints
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    On Sun, 2009-02-22 at 07:24 -0500, Frank Ch. Eigler wrote:
    > Hi -
    >
    > On Sun, Feb 22, 2009 at 01:14:36PM +0100, Peter Zijlstra wrote:
    > > > > I would like to never merge an ftrace_printk() user... just as I'd like
    > > > > to get rid of every marker.
    > > >
    > > > But why? They solve a problem well enough that Ingo had in effect
    > > > reinvented them on Friday.
    > >
    > > Because after a printk() debug spree, I don't commit them, I toss them
    > > out and keep the fix.
    >
    > Markers solve a problem closer to tracepoints than to debugging
    > printk's.

    Not so. In both cases the regular stuff (NMI trace, OOPS,
    function/graph/sched trace, etc) is not enough and you wish to augment
    its output.

    > In this context, the main difference between tracepoints is that
    > markers need almost no hand-written glue code of the sort that make up
    > ftrace engines that just trace simple values. Simpler & smaller code
    > for the same output seems like a win.

    Right, for dumb tracers that's true I suppose, however any
    high-bandwidth tracer will try to avoid putting silly ASCII strings in
    and will therefore need to write more glue code.

    Which reduces these default thingies to printk() level debugging.



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