Re: jiffies rollover, uptime etc.

Tim Schmielau (tim@physik3.uni-rostock.de)
Mon, 18 Feb 2002 23:32:03 +0100 (CET)


On Mon, 18 Feb 2002, Ben Greear wrote:

> I wonder, is it more expensive to write all drivers to handle the
> wraps than to take the long long increment hit? The increment is
> once every 10 miliseconds, right? That is not too often, all things
> considered...

This is just a matter of getting the signed/unsigned declarations right in
comparisons. (time_before and time_after macros were introduced to aid
here, hint!)
No overhead is involved here.

Actually, quite a few bug fixes in this area went into 2.4.18pre, with
some more to come in 2.4.19pre.

>
> Maybe the non-atomicity of the long long increment is the problem?

Yes.

> Does this problem still exist on 64-bit machines?
>

No.

> THanks,
> Ben

Tim

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/