Messages in this thread | | | Date | Tue, 19 Feb 2008 10:28:46 +0100 | From | Andi Kleen <> | Subject | Re: [PATCH 1/3] Fix Unlikely(x) == y |
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> Sometimes, for performance critical paths, I would like gcc to be dumb and > follow *my* code and not its hard-coded probabilities.
If you really want that, simple: just disable optimization @)
> Maybe one thing we would need would be the ability to assign probabilities > to each branch based on what we expect, so that gcc could build a better > tree keeping most frequently used code tight.
Just use profile feedback then for user space. I don't think it's a good idea for kernel code though because it leads to unreproducible binaries which would wreck the development model.
> Hmm I've just noticed -fno-guess-branch-probability in the man, I never tried > it.
Or -fno-reorder-blocks
-Andi
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