On Fri, 14 Dec 2007 01:33:45 +0100 Andi Kleen <andi@xxxxxxxxxxxxxx> wrote: > 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. So... once we've moved all read-mostly variables into __read_mostly, what is left behind in bss? All the write-often variables. All optimally packed together to nicely maximise cacheline sharing. - 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
