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    SubjectRe: CONFIG_FRAME_POINTER [was [PATCH] x86: BUILD_IRQ say .text]
    On Mon, 28 Jul 2008, Ingo Molnar wrote:
    > * Hugh Dickins <hugh@veritas.com> wrote:
    >
    > > I rather think CONFIG_FRAME_POINTER shouldn't exist at all (or be a
    > > private, config-user-invisible, specific-to-a-few-arches thing): what
    > > one wants to configure is how far to sacrifice cpu performance and
    > > kernel smallness to getting a good stacktrace. Frame pointer is just
    > > an implementation detail on that, appropriate to some arches. Perhaps
    > > three settings: no stacktrace, fair stacktrace, best stacktrace.
    >
    > actually, we consciously use and rely on frame pointers on x86. The
    > runtime cost on 64-bit is miniscule and the improved backtrace output in
    > recent kernels makes backtraces _much_ easier to interpret:

    Just to clarify, no way was I criticizing the use of frame pointers
    on x86. What I don't care for is that CONFIG_FRAME_POINTER is used
    by common code (e.g. top level Makefile, and various debug Kconfigs),
    when I see it as an arch-specific technique for getting best stacktrace.

    Hugh


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