On Wed, Jul 09, 2014 at 11:31:45PM +0200, Thomas Hellström wrote: > >Speaking of verbose, all the likely/unlikely annotations should be > >removed. > > Is this your personal opinion or has there been some kind of kernel > developer agreement not to add this annotation and remove it from > the kernel tree? If not, I prefer to keep it. It obviously makes the code less readable. It makes a small speedup if the code is called 10000 times with the and the expected value is true every time. If more than 1 out of 10000 values is unexpected then it is a slow down. There are two rules of thumb for likely/unlikely: 1) Don't use it in the drivers/ directory. 2) Or don't use it without benchmarking it. These are general rules, not mine. In the olden days we used to use it more often but then people did benchmarking and likely/unlikely annotations didn't make a single measurable difference on normal benchmarks at all. Maybe on a micro benchmark. Also perhaps in those days people hadn't done branch profiling so we were getting a lot of unexpected conditions and the slow downs were canceling the speed ups. regards, dan carpenter _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
