Re: [PATCH v3 00/11] PCID and improved laziness

From	Andy Lutomirski <luto@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 00/11] PCID and improved laziness
Date	2017-06-22 07:30 +0200
Message-ID	<tV2QN-cZ-5@gated-at.bofh.it> (permalink)
References	<tUGnf-1Tn-3@gated-at.bofh.it> <tUSy6-1pG-39@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Jun 21, 2017 at 11:23 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Tue, Jun 20, 2017 at 10:22 PM, Andy Lutomirski <luto@kernel.org> wrote:
>> There are three performance benefits here:
>
> Side note: can you post the actual performance numbers, even if only
> from some silly test program on just one platform? Things like lmbench
> pipe benchmark or something?
>
> Or maybe you did, and I just missed it. But when talking about
> performance, I'd really like to always see some actual numbers.

Here are some timings using KVM:

pingpong between two processes using eventfd:
patched: 883ns
unpatched: 1046ns (with considerably higher variance)

madvise(MADV_DONTNEED); write to the page; switch CPUs:
patched: ~12.5us
unpatched: 19us

The latter test is a somewhat contrived example to show off the
improved laziness.  Current kernels send an IPI on each iteration if
the system is otherwise idle.

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[PATCH v3 00/11] PCID and improved laziness Andy Lutomirski <luto@kernel.org> - 2017-06-21 07:30 +0200
  [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using PCID Andy Lutomirski <luto@kernel.org> - 2017-06-21 07:30 +0200
    Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using  PCID Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 15:40 +0200
      Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using  PCID Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 15:50 +0200
      Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using PCID Andy Lutomirski <luto@kernel.org> - 2017-06-22 05:00 +0200
        Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using  PCID Thomas Gleixner <tglx@linutronix.de> - 2017-06-22 14:30 +0200
          Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using PCID Andy Lutomirski <luto@kernel.org> - 2017-06-22 20:20 +0200
            Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using  PCID Thomas Gleixner <tglx@linutronix.de> - 2017-06-22 23:30 +0200
              Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using PCID Andy Lutomirski <luto@kernel.org> - 2017-06-23 05:10 +0200
                Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using  PCID Thomas Gleixner <tglx@linutronix.de> - 2017-06-23 09:30 +0200
    Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using  PCID Nadav Amit <nadav.amit@gmail.com> - 2017-06-22 18:20 +0200
      Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using PCID Andy Lutomirski <luto@kernel.org> - 2017-06-22 20:20 +0200
    Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using  PCID Borislav Petkov <bp@alien8.de> - 2017-06-26 18:10 +0200
  [PATCH v3 08/11] x86/mm: Disable PCID on 32-bit kernels Andy Lutomirski <luto@kernel.org> - 2017-06-21 07:30 +0200
    Re: [PATCH v3 08/11] x86/mm: Disable PCID on 32-bit kernels Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 11:30 +0200
    Re: [PATCH v3 08/11] x86/mm: Disable PCID on 32-bit kernels Borislav Petkov <bp@alien8.de> - 2017-06-23 11:30 +0200
  [PATCH v3 02/11] x86/ldt: Simplify LDT switching logic Andy Lutomirski <luto@kernel.org> - 2017-06-21 07:30 +0200
    Re: [PATCH v3 02/11] x86/ldt: Simplify LDT switching logic Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 10:10 +0200
    Re: [PATCH v3 02/11] x86/ldt: Simplify LDT switching logic Borislav Petkov <bp@alien8.de> - 2017-06-21 11:50 +0200
    [tip:x86/mm] x86/ldt: Simplify the LDT switching logic tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2017-06-22 13:20 +0200
  [PATCH v3 01/11] x86/mm: Don't reenter flush_tlb_func_common() Andy Lutomirski <luto@kernel.org> - 2017-06-21 07:30 +0200
    Re: [PATCH v3 01/11] x86/mm: Don't reenter flush_tlb_func_common() Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 10:10 +0200
    Re: [PATCH v3 01/11] x86/mm: Don't reenter flush_tlb_func_common() Borislav Petkov <bp@alien8.de> - 2017-06-21 10:50 +0200
      Re: [PATCH v3 01/11] x86/mm: Don't reenter flush_tlb_func_common() Andy Lutomirski <luto@kernel.org> - 2017-06-21 17:20 +0200
    Re: [PATCH v3 01/11] x86/mm: Don't reenter flush_tlb_func_common() Nadav Amit <nadav.amit@gmail.com> - 2017-06-22 01:30 +0200
      Re: [PATCH v3 01/11] x86/mm: Don't reenter flush_tlb_func_common() Andy Lutomirski <luto@kernel.org> - 2017-06-22 04:30 +0200
        Re: [PATCH v3 01/11] x86/mm: Don't reenter flush_tlb_func_common() Ingo Molnar <mingo@kernel.org> - 2017-06-22 09:40 +0200
  [PATCH v3 06/11] x86/mm: Rework lazy TLB mode and TLB freshness tracking Andy Lutomirski <luto@kernel.org> - 2017-06-21 07:30 +0200
    Re: [PATCH v3 06/11] x86/mm: Rework lazy TLB mode and TLB freshness  tracking Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 11:10 +0200
      Re: [PATCH v3 06/11] x86/mm: Rework lazy TLB mode and TLB freshness tracking Andy Lutomirski <luto@kernel.org> - 2017-06-21 18:30 +0200
        Re: [PATCH v3 06/11] x86/mm: Rework lazy TLB mode and TLB freshness  tracking Borislav Petkov <bp@alien8.de> - 2017-06-21 19:30 +0200
    Re: [PATCH v3 06/11] x86/mm: Rework lazy TLB mode and TLB freshness  tracking Borislav Petkov <bp@alien8.de> - 2017-06-22 17:00 +0200
      Re: [PATCH v3 06/11] x86/mm: Rework lazy TLB mode and TLB freshness tracking Andy Lutomirski <luto@kernel.org> - 2017-06-22 19:50 +0200
        Re: [PATCH v3 06/11] x86/mm: Rework lazy TLB mode and TLB freshness  tracking Borislav Petkov <bp@alien8.de> - 2017-06-22 21:10 +0200
    Re: [PATCH v3 06/11] x86/mm: Rework lazy TLB mode and TLB freshness  tracking Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-06-23 15:40 +0200
      Re: [PATCH v3 06/11] x86/mm: Rework lazy TLB mode and TLB freshness tracking Andy Lutomirski <luto@kernel.org> - 2017-06-23 17:30 +0200
  [PATCH v3 04/11] x86/mm: Give each mm TLB flush generation a unique ID Andy Lutomirski <luto@kernel.org> - 2017-06-21 07:30 +0200
    Re: [PATCH v3 04/11] x86/mm: Give each mm TLB flush generation a  unique ID Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 10:10 +0200
    Re: [PATCH v3 04/11] x86/mm: Give each mm TLB flush generation a  unique ID Borislav Petkov <bp@alien8.de> - 2017-06-21 12:40 +0200
      Re: [PATCH v3 04/11] x86/mm: Give each mm TLB flush generation a  unique ID Andy Lutomirski <luto@kernel.org> - 2017-06-21 18:40 +0200
        Re: [PATCH v3 04/11] x86/mm: Give each mm TLB flush generation a  unique ID Borislav Petkov <bp@alien8.de> - 2017-06-21 19:10 +0200
    Re: [PATCH v3 04/11] x86/mm: Give each mm TLB flush generation a  unique ID Borislav Petkov <bp@alien8.de> - 2017-06-21 19:50 +0200
      Re: [PATCH v3 04/11] x86/mm: Give each mm TLB flush generation a  unique ID Andy Lutomirski <luto@kernel.org> - 2017-06-22 04:40 +0200
  [PATCH v3 10/11] x86/mm: Enable CR4.PCIDE on supported systems Andy Lutomirski <luto@kernel.org> - 2017-06-21 07:30 +0200
    Re: [PATCH v3 10/11] x86/mm: Enable CR4.PCIDE on supported systems Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 11:40 +0200
      Re: [PATCH v3 10/11] x86/mm: Enable CR4.PCIDE on supported systems Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 15:50 +0200
      Re: [PATCH v3 10/11] x86/mm: Enable CR4.PCIDE on supported systems Andy Lutomirski <luto@kernel.org> - 2017-06-21 22:40 +0200
    Re: [PATCH v3 10/11] x86/mm: Enable CR4.PCIDE on supported systems Borislav Petkov <bp@alien8.de> - 2017-06-23 14:00 +0200
      Re: [PATCH v3 10/11] x86/mm: Enable CR4.PCIDE on supported systems Andy Lutomirski <luto@kernel.org> - 2017-06-23 17:30 +0200
    Re: [PATCH v3 10/11] x86/mm: Enable CR4.PCIDE on supported systems Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-06-23 15:40 +0200
  [PATCH v3 07/11] x86/mm: Stop calling leave_mm() in idle code Andy Lutomirski <luto@kernel.org> - 2017-06-21 07:30 +0200
    Re: [PATCH v3 07/11] x86/mm: Stop calling leave_mm() in idle code Thomas Gleixner <tglx@linutronix.de> - 2017-06-21 11:30 +0200
      Re: [PATCH v3 07/11] x86/mm: Stop calling leave_mm() in idle code Andy Lutomirski <luto@kernel.org> - 2017-06-21 18:30 +0200
    Re: [PATCH v3 07/11] x86/mm: Stop calling leave_mm() in idle code Borislav Petkov <bp@alien8.de> - 2017-06-23 11:10 +0200
  Re: [PATCH v3 00/11] PCID and improved laziness Linus Torvalds <torvalds@linux-foundation.org> - 2017-06-21 20:30 +0200
    Re: [PATCH v3 00/11] PCID and improved laziness Andy Lutomirski <luto@kernel.org> - 2017-06-22 07:30 +0200

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