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

From: Jeff Garzik <[email-masked]>
Date: Fri, 26 Mar 2004 14:03:01 -0500

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