On 03/01/16 13:32, Peter Zijlstra wrote: > On Tue, Mar 01, 2016 at 08:23:12PM +0000, Mathieu Desnoyers wrote: >> I think it's important that user-space fast-paths can quickly >> detect whether the feature is enabled without having to rely on >> always reading a separate cache-line. I've put together an ABI >> proposal that take into account the feedback received so far. > > Nah, adding detectoring code to fast paths is silly, makes them less > fast. Doesn't userspace have self modifying code? I know that at least > glibc does linker trickery to call different functions depending on > runtime context. > No, userspace does not have self-modifying code. The glibc indirect function is done at dynamic link time; it is also worth noting that resolving global symbols through dynamic linking often requires an indirect call. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
