Messages in this thread | | | Subject | Re: [PATCH 0/3] Use global pages with PTI | From | Dave Hansen <> | Date | Thu, 15 Feb 2018 15:55:45 -0800 |
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On 02/15/2018 09:47 AM, Linus Torvalds wrote: > On Thu, Feb 15, 2018 at 5:20 AM, Dave Hansen > <dave.hansen@linux.intel.com> 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.
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