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    SubjectRe: [RFC] [PATCH 1/1] perf: add support for arch-dependent symbolic event names to "perf stat"

    * Paul Mackerras <> wrote:

    > On Thu, Mar 11, 2010 at 01:46:08PM +0100, Ingo Molnar wrote:
    > >
    > > * Corey Ashford <> wrote:
    > >
    > > > On 3/3/2010 6:30 PM, Corey Ashford wrote:
    > > > >For your review, this patch adds support for arch-dependent symbolic
    > > > >event names to the "perf stat" tool, and could be expanded to other
    > > > >"perf *" commands fairly easily, I suspect.
    > > I'm quite much against stop-gap measures like this - they tend to become
    > > tomorrow's impossible-to-remove quirk.
    > >
    > > If you want extensible events you can already do it by providing an ftrace
    > > tracepoint event via TRACE_EVENT. They are easy to add and ad-hoc, and are
    > > supported throughout by perf.
    > If I've understood correctly what Corey is doing, I think you're missing the
    > point. The idea, I thought, was to provide a way to be able to use symbolic
    > names for raw hardware events rather than just numbers. I don't see how
    > ftrace tracepoint events are relevant to that.

    tracepoints are relevant because they are the currently best way of how we
    assign symbolic names to various kernel-internal events. For ad-hoc usecases
    like this:

    I'd much rather see that facility used (and, to the extent needed, extended)
    to provide support for rare arch events that we dont want to enumerate in a
    generic way.

    Or, if the events are important enough to be hardcoded into the perf ABI
    itself, they should be generalized in a meaningful way - even if you dont
    expect them to show up on other CPUs.


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