"David S. Miller" <[EMAIL PROTECTED]> writes: > From: Alexey Dobriyan <[EMAIL PROTECTED]> > Date: Sat, 27 Aug 2005 02:58:48 +0400 > > > What's the point of having unlikely() attached to every possible if ()? > > If can result in smaller code, for one thing, even if it > isn't a performance critical path.
Really? At least on x86 it tends to generate bigger code when block reordering is enabled because a jump forward and a jump backward and a possible label alignment are bigger than just a single jump forward. But then it doesn't make that much difference because the compiler does it on its own for every block. On x86-64 I keep it disabled because: - it generates bigger code - it makes the assembly code unreadable - it doesn't seem to help that much on modern CPUs with good branch prediction and big icaches anyways. -Andi (who originally introduced likely/unlikely, but regrets it these days because it's far overused and makes code uglier everywhere) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
