Messages in this thread | | | Date | Thu, 11 Oct 2007 21:41:43 -0500 | From | Olof Johansson <> | Subject | Re: [PATCH 2/2] powerpc: Switch to generic WARN_ON()/BUG_ON() |
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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.
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