Re: [PATCH] deinline sleep/delay functions

Russell King
2005-06-30T12:05:03Z

On Thu, Jun 30, 2005 at 02:44:51PM +0300, Denis Vlasenko wrote:
> On Thursday 30 June 2005 14:21, Russell King wrote:
> > The maximum delay is dependent on the architecture implementation,
> > and it depends on bogomips. There is no one single value for it.
> > Architectures have to decide this from the way that they do the
> > math and the expected range of bogomips.
>
> In example I posted these limitations are lifted. Granted these
> limitations were not critical, but removing them can't do harm,
> I guess?

They're lifted poorly. You include a mandatory division in the path.
On systems where division has to be done in code, this is not acceptable,
especially when we're trying to get short delays on embedded CPUs
running below 100MHz. The time it takes to do the division could
swamp the required delay value.

--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core