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

[Jeff Garzik <jgarzik@xxxxxxxxx>]

Sridhar Samudrala wrote:
> 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.
We'll definitely want to return 1 rather than zero, for the uses in my 
drivers, at least...
        Jeff