linux-kernel - Re: [PATCH v2] KVM: LAPIC: Loose fluctuation filter for auto tune lapic_timer_advance

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Message-ID: <ea06c6bb-c6ff-ef34-55ca-c58cb77ed39e@redhat.com>
Date:   Thu, 26 Sep 2019 12:25:21 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Wanpeng Li <kernellwp@...il.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     Radim Krčmář <rkrcmar@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>
Subject: Re: [PATCH v2] KVM: LAPIC: Loose fluctuation filter for auto tune
 lapic_timer_advance_ns

On 26/09/19 02:54, Wanpeng Li wrote:
> -#define LAPIC_TIMER_ADVANCE_ADJUST_MIN 100
> -#define LAPIC_TIMER_ADVANCE_ADJUST_MAX 5000
> -#define LAPIC_TIMER_ADVANCE_ADJUST_INIT 1000
> +#define LAPIC_TIMER_ADVANCE_EXPIRE_MIN	100
> +#define LAPIC_TIMER_ADVANCE_EXPIRE_MAX	10000
> +#define LAPIC_TIMER_ADVANCE_NS_INIT	1000
> +#define LAPIC_TIMER_ADVANCE_NS_MAX     5000

I think the old #define value is good.  What about:

-#define LAPIC_TIMER_ADVANCE_ADJUST_MIN 100
-#define LAPIC_TIMER_ADVANCE_ADJUST_MAX 5000
-#define LAPIC_TIMER_ADVANCE_ADJUST_INIT 1000
+#define LAPIC_TIMER_ADVANCE_ADJUST_MIN 100	/* clock cycles */
+#define LAPIC_TIMER_ADVANCE_ADJUST_MAX 10000	/* clock cycles */
+#define LAPIC_TIMER_ADVANCE_NS_INIT	1000
+#define LAPIC_TIMER_ADVANCE_NS_MAX     5000

?

Thanks,

Paolo