On Tue, 2007-03-27 at 09:17 -0700, Allexio Ju wrote: > On Thu, 2007-03-22 at 2007 2:24 AM, Arjan van de Ven wrote: > > (I assume you're aware that likely/unlikely should only be > > used for 99:1 or higher ratios, this one looks correct for sure) > Could you share details of reasons why those macros should be used in the way? > I thought those macros simply tell compiler to layout code in such a > way that minimizes unnecessary jumps.
it's more than that. it generally also tells the processor what the branch will be, at which point most processors disable their own branch prediction logic. Trying to hand-layout code is almost always a mistake... don't do that. GCC also is quite good at recognizing certain patterns to keep the code flow working. Trying to override that only hurts... -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
