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    SubjectRe: [performance problem] CONFIG_DYNAMIC_FTRACE: Increased kernel build times
    2009/10/23 Ingo Molnar <mingo@elte.hu> wrote:
    >
    > Steve,
    >
    > i did an 64-bit allyesconfig build test (with debug_info disabled), with
    > and without CONFIG_DYNAMIC_FTRACE set.
    >
    > The build time results are:
    >
    >  -CONFIG_DYNAMIC_FTRACE:   266.30
    >  +CONFIG_DYNAMIC_FTRACE:   296.07 (+11.2%)
    >
    > So we get more than 10% build time overhead.
    >
    > That's quite high - higher than what i remember having measured
    > originally when the first iteration of the mcount code went in.
    >
    > This extra overhead comes from the mcount post-processing script
    > (scripts/recordmcount.pl) that runs objcopy as well and is written in
    > Perl. I think this whole angle needs to be improved - 10% is way too
    > high of a price to pay.

    Hi Ingo, do you still have the profiling data to share with us?
    Was the problem more in objcopy / objdump, rather than in the perl script
    itself?

    Thanks

    John
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