On Mon, Nov 10, 2008 at 04:10:47PM +0100, Nick Piggin wrote: > Static branch hint instruction could indeed turn off dynamic prediction > so in that cause it would always mispredict even if the workload was > continually going the other way. It's not just turning them off. In many cpu microarchitectures a wrong static prediction means an pipeline stall that's much worse than a dynamic mispredict because that information is interpreted much deeper in the pipeline. Please just don't use likely/unlikely unless really nessecary. > However, I think you have to consider frequency, and also relative > importance of each case. This is going to be taken on sys_sync, and > sys_umount. And not taken for pdflush writeout. Yes. So dynamic branch prediction will get this perfectly right on any reasonable CPU. > > > + /* see dquot.c comment */ > > > > Not an exactly useful comment :) > > /* see fs/dquot.c:add_dquot_ref() comment */ ? > > Thanks, I will repost with these changes after waiting for more feedback. Please just copy the comment over. Looking somewhere else to follow a comment is not very nice (and this is the more important file compared to dquot.c anyway :)) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
