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Date: Wed, 12 May 2004 14:33:07 -0700 (PDT)
From: Davide Libenzi <davidel@xmailserver.org>
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To: Valdis.Kletnieks@vt.edu
cc: Ingo Molnar <mingo@elte.hu>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Netdev <netdev@oss.sgi.com>
Subject: Re: MSEC_TO_JIFFIES is messed up... 
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On Wed, 12 May 2004 Valdis.Kletnieks@vt.edu wrote:

> On Wed, 12 May 2004 22:50:28 +0200, Ingo Molnar said:
> 
> > Content-Disposition: attachment; filename="hz-cleanup-2.6.6-A2"
> > 
> > --- linux/include/linux/time.h.orig	
> > +++ linux/include/linux/time.h	
> > @@ -177,6 +177,24 @@ struct timezone {
> >  	(SH_DIV((MAX_JIFFY_OFFSET >> SEC_JIFFIE_SC) * TICK_NSEC, NSEC_PER_SEC, 
> 1) - 1)
> >  
> >  #endif
> > +
> > +/*
> > + * Convert jiffies to milliseconds and back.
> > + *
> > + * Avoid unnecessary multiplications/divisions in the
> > + * two most common HZ cases:
> > + */
> > +#if HZ == 1000
> > +# define JIFFIES_TO_MSECS(x)	(x)
> > +# define MSECS_TO_JIFFIES(x)	(x)
> > +#elif HZ == 100
> > +# define JIFFIES_TO_MSECS(x)	((x) * 10)
> > +# define MSECS_TO_JIFFIES(x)	((x) / 10)
> > +#else
> > +# define JIFFIES_TO_MSECS(x)	((x) * 1000 / HZ)
> > +# define MSECS_TO_JIFFIES(x)	((x) * HZ / 1000)
> > +#endif
> > +
> 
> Looks good to me.. :)

Guys, why don't you leave the compiler to do its job?



- Davide