Messages in this thread | | | Date | Wed, 16 Jan 2002 00:14:50 -0500 | From | Jeff Garzik <> | Subject | Re: likely/unlikely |
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David Schwartz wrote: > > By the way, has anybody actually benchmarked these macros to see if they > make any difference. I did a few quick inexact benchmarks on test code and > found that in most cases there was no difference and in some cases code was > made worse.
likely/unlikely set the branch prediction values to 99% or 1% respectively. If this causes the code generated to perform less optimally than without, I'm sure the gcc guys would be -very- interested to hear that...
-- Jeff Garzik | Alternate titles for LOTR: Building 1024 | Fast Times at Uruk-Hai MandrakeSoft | The Took, the Elf, His Daughter and Her Lover | Samwise Gamgee: International Hobbit of Mystery - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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