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From:   Wanpeng Li <kernellwp@gmail.com>
Date:   Wed, 23 Oct 2019 17:25:20 +0800
Message-ID: <CANRm+Cx41peFT9WpqGjZcYDHiXsSAoJ-ONgO-c9t6cJ0puQQuQ@mail.gmail.com>
Subject: Re: [PATCH v2] sched/nohz: Optimize get_nohz_timer_target()
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, kvm <kvm@vger.kernel.org>,
        Frederic Weisbecker <frederic@kernel.org>
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On Wed, 23 Oct 2019 at 16:29, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> On Wed, 23 Oct 2019, Wanpeng Li wrote:
> > I didn't see your refactor to get_nohz_timer_target() which you
> > mentioned in IRC after four months, I can observe cyclictest drop from
> > 4~5us to 8us in kvm guest(we offload the lapic timer emulation to
> > housekeeping cpu to avoid timer fire external interrupt on the pCPU
> > which vCPU resident incur a vCPU vmexit) w/o this patch in the case of
> > there is no busy housekeeping cpu. The score can be recovered after I
> > give stress to create a busy housekeeping cpu.
> >
> > Could you consider applying this patch for temporary since I'm not
> > sure when the refactor can be ready.
>
> Yeah. It's delayed (again).... Will pick that up.

Sorry, you will pick up the patch or refactor? :)

    Wanpeng