Kyle McMartin <kyle@xxxxxxxxxxx> writes: > I'd bet, in the __read_mostly case at least, that there's no > improvement in almost all cases. I bet you're wrong. Cache line behaviour is critical, much more than pipeline behaviour (which unlikely affects). That is because if you eat a cache miss it gets really expensive, which e.g. a mispredicted jump is relatively cheap in comparison. We're talking one or more orders of magnitude. I admit I'm to blame for both (submitted unlikely and asked for __read_mostly) and I now consider unlikely a mistake now by hindsight, but still think __read_mostly was a good idea. There is one potential problem in that if __read_mostly is used too aggressively then the non __read_mostly variables will be all "write mostly" with nothing inbetween and that could lead to more false sharing, but so far this doesn't seem to be a big problem (and that one could be solved too) -Andi - To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
