On 01/13/2016 03:51 PM, Andy Lutomirski wrote: > On Wed, Jan 13, 2016 at 3:43 PM, Dave Hansen > <dave.hansen@xxxxxxxxxxxxxxx> wrote: >> On 01/13/2016 03:35 PM, Andy Lutomirski wrote: >>> Can anyone here ask a hardware or microcode person what's going on >>> with CR3 writes possibly being faster than INVPCID? Is there some >>> trick to it? >> >> I just went and measured it myself this morning. "INVPCID Type 3" (all >> contexts no global) on a Skylake system was 15% slower than a CR3 write. >> >> Is that in the same ballpark from what you've observed? > > It's similar, except that I was comparing "INVPCID Type 1" (single > context no globals) to a CR3 write. Ahh, because you're using PCID... That one I saw as being ~1.85x the number of cycles that a CR3 write was. > Type 2, at least, is dramatically faster than the pair of CR4 writes > it replaces. Yeah, I saw the same thing. Type 2 was ~2.4x faster than the CR4 writes. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>