On Wed, 2007-01-03 at 12:44 +0000, Alan wrote: > > > fixed. At that point an i686 kernel would contain i686 instructions and > > > actually run on all i686 processors ending all the i586 pain for most > > > users and distributions. > > > > Could you explain why CMOV is pointless now? Are there any benchmarks > > proving that? > > Take a look at the recent ffmpeg bits on the mplayer list for one example > I have to hand - P4 cmov is pretty slow. The crypto folks find the same > things.
cmov is effectively the same cost as a compare and jump, in both cases the cpu needs to do a prediction, and on a mispredict, restart. the reason cmov can make sense is because it's smaller code... -- 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-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
