Re: [PATCH/RFC] msleep() with hrtimers

Nick Piggin
2007-07-18T16:29:36Z

Nish Aravamudan wrote:

> Well, before these changes, the only guarantee msleep() could make,
> just like the only guarantee schedule_timeout() could make, was that
> it would not return early. The 1-jiffy sleep was always tough to deal
> with, because of rounding and such. And it's simply exacerbated with
> HZ=100. It's not technically 20 times longer in all cases, it's 2
> jiffies longer, which depends on HZ, so varies from 2 msecs longer to
> 20 msecs longer.

I don't think you should rely on anything else actually, because Linux
is not an RT OS. If your driver needs a specific sequence in a given
amount of time, you have to do something like disable interrupts and
use delays.

--
SUSE Labs, Novell Inc.