On Thu, 25 Oct 2007 13:24:49 +1000 Nick Piggin <[EMAIL PROTECTED]> wrote:
> Hi, > > Andi spotted this exchange on the gcc list. I don't think he's > brought it up here yet, but it worries me enough that I'd like > to discuss it. > > Starts here > http://gcc.gnu.org/ml/gcc/2007-10/msg00266.html > > Concrete example here > http://gcc.gnu.org/ml/gcc/2007-10/msg00275.html > > Basically, what the gcc developers are saying is that gcc is > free to load and store to any memory location, so long as it > behaves as if the instructions were executed in sequence. > this optimization btw is a serious mis-optimization, it makes memory more dirty and causes cachelines to become unshared.... I'm sure it works great on microbenchmarks but it sucks bigtime for anything real - 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/
