Messages in this thread | | | Date | Sun, 21 Jun 2015 23:22:31 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH 0/3] TLB flush multiple pages per IPI v5 |
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On Tue, Jun 09, 2015 at 08:34:35AM -0700, Dave Hansen wrote: > On 06/09/2015 05:43 AM, Ingo Molnar wrote: > > +static char tlb_flush_target[PAGE_SIZE] __aligned(4096); > > +static void fn_flush_tlb_one(void) > > +{ > > + unsigned long addr = (unsigned long)&tlb_flush_target; > > + > > + tlb_flush_target[0]++; > > + __flush_tlb_one(addr); > > +} > > So we've got an increment of a variable in kernel memory (which is > almost surely in the L1), then we flush that memory location, and repeat > the increment.
BTW, Ingo, have you disabled direct mapping of kernel memory with 2M/1G pages for the test?
I'm just thinking if there is chance that the test shooting out 1G tlb entry. In this case we're measure wrong thing.
-- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
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