Re: [PATCH] Consolidate multiple implementations of jiffies-msecsconversions.

From: Sridhar Samudrala
Date: Fri Mar 26 2004 - 13:53:39 EST

On Fri, 26 Mar 2004, Edgar Toernig wrote:

> Sridhar Samudrala wrote:
> >
> > The following patch to 2.6.5-rc2 consolidates 6 different implementations
> > of msecs to jiffies and 3 different implementation of jiffies to msecs.
> > All of them now use the generic msecs_to_jiffies() and jiffies_to_msecs()
> > that are added to include/linux/time.h
> >[...]
> > -#define MSECS(ms) (((ms)*HZ/1000)+1)
> > -return (((ms)*HZ+999)/1000);
> > +return (msecs / 1000) * HZ + (msecs % 1000) * HZ / 1000;
> Did you check that all users of the new version will work correctly
> with your rounding? Explicit round-up of delays is often required,
> especially when talking to hardware...

I don't see any issues with the 2.6 default HZ value of 1000 as they become
no-ops and there is no need for any rounding.
I guess you are referring to cases when HZ < 1000(ex: 100) and msecs is
less than 10. In those cases, the new version returns 0, whereas some of the
older versions return 1.

If i am not mistaken, Jeff Garjik/David Miller are the maintainers for most
of the users of these routines and i have got an OK from them.

The only other place where the older version is different is

Dave, Jeff
Do you see any issues with the new generic versions of these routines?

> Ciao, ET.
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