On 02/15/2018 09:47 AM, Linus Torvalds wrote: > On Thu, Feb 15, 2018 at 5:20 AM, Dave Hansen > <dave.hansen@xxxxxxxxxxxxxxx> wrote: >> During the switch over to PTI, we seem to have lost our ability to have >> GLOBAL mappings. ... > Did you perhaps re-run any benchmark numbers just to verify? Because > it's always good to back up patches that should improve performance > with actual numbers.. Same test as last time except I'm using all 4 cores on a Skylake desktop instead of just 1. The test is this: > https://github.com/antonblanchard/will-it-scale/blob/master/tests/lseek1.c With PCIDs, lseek()s/second go up around 2% to 3% with the these patches enabling the global bit (it's noisy). I measured it at 3% before, so definitely the same ballpark. That was also before all of Andy's trampoline stuff and the syscall fast path removal. -- 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>
