* Dave Hansen <dave.hansen@xxxxxxxxx> wrote: > tl;dr: Kernels with pagetable isolation using INVPCID compile kernels > 0.58% faster than using the deferred CR3 write. This tends to say that > we should leave things as-is and keep using INVPCID, but it's far from > definitive. Agreed, thanks for the detailed testing! > If folks have better ideas for a test methodology, or specific workloads or > hardware where you want to see this tested, please speak up. I had a look at the numbers and it all looks valid and good to me too - it's also the intuitive result IMHO. I suspect there might be synthetic cache-hot workloads where the +330 cycles cost of INVPCID is higher than that of the extra TLB miss costs of a CR3 flush - but we do know that this offset is constant, while the cost of flushing all TLBs ever increases with the future increases of the TLB cache. Thanks, Ingo -- 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>
