From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dario Faggioli <dario.faggioli@citrix.com>
Subject: Re: [PATCH] credit: track residual from divisions done
 during accounting
Date: Fri, 22 Feb 2013 18:26:43 +0100
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To: Jan Beulich <JBeulich@suse.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>, xen-devel <xen-devel@lists.xen.org>
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On Mon, 2013-02-18 at 12:37 +0000, Jan Beulich wrote:
> --- a/xen/common/sched_credit.c
> +++ b/xen/common/sched_credit.c
>
> @@ -242,6 +244,7 @@ __runq_remove(struct csched_vcpu *svc)
>  static void burn_credits(struct csched_vcpu *svc, s_time_t now)
>  {
>      s_time_t delta;
> +    uint64_t val;
>      unsigned int credits;
> =20
>      /* Assert svc is current */
> @@ -250,7 +253,10 @@ static void burn_credits(struct csched_v
>      if ( (delta =3D now - svc->start_time) <=3D 0 )
>          return;
> =20
> -    credits =3D (delta*CSCHED_CREDITS_PER_MSEC + MILLISECS(1)/2) / MILLI=
SECS(1);
> +    val =3D delta * CSCHED_CREDITS_PER_MSEC + svc->residual;
> +    svc->residual =3D do_div(val, MILLISECS(1));
> +    credits =3D val;
> +    ASSERT(credits =3D=3D val);

I may be missing something, but how can the assert ever be false, given
the assignment right before it?

Regards,
Dario

--=20
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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