On 01/05/2012 04:14 PM, David Laight wrote: > >> We don't need it as debug calls already have a log level and >> compiler should be smart enough to optimise away the code when >> ath6kl debug code is not enabled. > > Have you checked? No, I just assumed so. > I think you are assuming that because the called function collapses, > the call will be removed allowing the loop to be removed. I suspect > this is only true if the function is inlined. IIRC the normal linkage > rules mean that only static functions are candidates for inlining. I think you are right. But while I investigated more I noticed that ath6kl_dump_registers() will be an empty static inline whenever CONFIG_ATH6KL_DEBUG is disabled and that will make sure that the whole function is not included. So whenever ath6kl debug code is enabled there is a small performance hit, but it's so small that IMHO we don't need to worry about it. And for optimal performance CONFIG_ATH6KL_DEBUG should be disabled anyway. What do you think? Kalle -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
