On Fri, Sep 11, 2009 at 7:24 AM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > > On Fri, 11 Sep 2009, Luis R. Rodriguez wrote: >> >> That is the way I had it originally before submission, and I >> completely agree its reasonable to not incur additional cost at the >> expense of having two separate read/write paths, and perhaps we should >> only incur the extra cost on routines shared between >> ath9k/ath9k/ath9k_htc. But -- is there really is a measurable cost >> penalty? > > There's a measurable size penalty, at least. My tests so far yield no performance difference but I'm sure there is some, maybe as Jouni noted, more visible on embedded systems. > In fact, if you know what kind of IO op it is (ie "it's always MMIO"), > you'd be even better using "writel()" directly, Heh.. you realize I tried to document such a thing a while ago and it seems you opposed it [1]? [1] http://lkml.indiana.edu/hypermail/linux/kernel/0709.2/0593.html Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
