Re: [PATCH 06/10] time: Cap clocksource reads to the clocksource max_cycles value

From: Linus Torvalds
Date: Mon Jan 12 2015 - 14:03:00 EST


On Tue, Jan 13, 2015 at 7:54 AM, John Stultz <john.stultz@xxxxxxxxxx> wrote:
>
> So I disagree this is papering over the problem.

Indeed. It's making things more robust in the face of _known_ issues.
Even with a perfectly designed timer (which we so far have never
seen), interrupts get delayed etc, so trying to stretch it to the
limit of the timer is simply not a good idea. Quite the reverse.

More importantly, if the timer is actually any good, the safety margin
won't actually matter, since the timer cycle is so long that 50% of
essentially infinite is still essentially infinite.

And if the timer isn't very good, then some slop for safety is just
being robust.

At no point is it "papering over" anything at all.

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