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    SubjectRe: [PATCH 2/2] powerpc: Switch to generic WARN_ON()/BUG_ON()
    On Thu, Oct 11, 2007 at 10:04:19PM -0400, Kyle McMartin wrote:
    > On Fri, Oct 12, 2007 at 11:23:39AM +1000, Paul Mackerras wrote:
    > > Olof Johansson writes:
    > >
    > > > Not using the ppc-specific WARN_ON/BUG_ON constructs actually saves about
    > > > 4K text on a ppc64_defconfig. The main reason seems to be that prepping
    > > > the arguments to the conditional trap instructions is more work than
    > > > just doing a compare and branch.
    > >
    > > It might be more instructions but it takes fewer cycles, I would
    > > expect. Do you have the actual instruction sequences to compare?
    > >
    >
    > I really hope WARN_ON/BUG_ON aren't hotpaths on powerpc. ;-)

    Not the taken branch of them, no. :) But making it past them as fast
    as possible when they're not tripping is always good.


    -Olof
    -
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