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Date: Wed, 16 Jan 2002 15:00:12 -0800 (PST)
From: Davide Libenzi <davidel@xmailserver.org>
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To: Alexei Podtelezhnikov <apodtele@mccammon.ucsd.edu>
cc: linux-kernel@vger.kernel.org
Subject: Re: [o(1) sched J0] higher priority smaller timeslices, in fact
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On Wed, 16 Jan 2002, Alexei Podtelezhnikov wrote:

>
> The comment and the actual macros are inconsistent.
> positive number * (19-n) is a decreasing function of n!

# man nice


> + * The higher a process's priority, the bigger timeslices
> + * it gets during one round of execution. But even the lowest
> + * priority process gets MIN_TIMESLICE worth of execution time.
> + */
>
> -#define NICE_TO_TIMESLICE(n)   (MIN_TIMESLICE + \
> -	((MAX_TIMESLICE - MIN_TIMESLICE) * (19 - (n))) / 39)
> +#define NICE_TO_TIMESLICE(n) (MIN_TIMESLICE + \
> +	((MAX_TIMESLICE - MIN_TIMESLICE) * (19-(n))) / 39)
>
> I still suggest a different set as faster and more readable at least to
> me. Just two operations instead of 4!

this seems quite readable to me, it's the equation at page 1 of any know
linear geometry book.




- Davide


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