Messages in this thread | | | Date | Mon, 4 Dec 2017 23:51:44 +0100 | From | Peter Zijlstra <> | Subject | Re: [patch 55/60] x86/mm: Use INVPCID for __native_flush_tlb_single() |
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On Mon, Dec 04, 2017 at 02:25:43PM -0800, Andy Lutomirski wrote: > On Mon, Dec 4, 2017 at 6:08 AM, Thomas Gleixner <tglx@linutronix.de> wrote: > > From: Dave Hansen <dave.hansen@linux.intel.com> > > > > This uses INVPCID to shoot down individual lines of the user mapping > > instead of marking the entire user map as invalid. This > > could/might/possibly be faster. > > > > This for sure needs tlb_single_page_flush_ceiling to be redetermined; > > esp. since INVPCID is _slow_. > > I'm wondering if INVPCID is *so* slow that this patch is entirely > counterproductive.
We should find some of the benchmarks that were used to determine tlb_single_page_flush_ceiling and measure. I've not gotten around to doing either.
Someone called Dave Hansen did that patch and might still have something lying around to help with that:
a5102476a24b ("x86/mm: Set TLB flush tunable to sane value (33)")
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