On 12/19/2013 09:36 AM, Peter Zijlstra wrote: > On Thu, Dec 19, 2013 at 06:25:35PM +0100, Peter Zijlstra wrote: >> That said, I would find it very strange indeed if a CLFLUSH doesn't also >> flush the store buffer. > > OK, it explicitly states it does not do that and you indeed need an > mfence before the clflush. > So, MONITOR is defined to be ordered as a load, which I think should be adequate, but I really wonder if we should have mfence on both sides of clflush. This now is up to 9 bytes, and perhaps pushing it a bit with how much we would be willing to patch out. On the other hand - the CLFLUSH seems to have worked well enough by itself, and this is all probabilistic anyway, so perhaps we should just leave the naked CLFLUSH in and not worry about it unless measurements say otherwise? -hpa -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html