Messages in this thread Patch in this message | | | Subject | Re: [PATCH 01/13] hrtimer: round up relative start time | From | Thomas Gleixner <> | Date | Mon, 13 Feb 2006 10:52:07 +0000 |
| |
On Mon, 2006-02-13 at 02:09 +0100, Roman Zippel wrote: > When starting a relative timer we have to round it up the next clock > tick to avoid an early expiry. The problem is that we don't know the > real clock resolution, so we have to assume the worst case, but it's > basically the same as the old code did, so it won't be worse than 2.6.15 > and with a better clock interface we can improve this. > > Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
NACK
This adds an artificial offset to the expiry time, for what reason? The expiry code makes sure that timers can not expire early. See:
timer = rb_entry(node, struct hrtimer, node); if (now.tv64 <= timer->expires.tv64) break;
in kernel/hrtimers.c:run_hrtimer_queue(), where now is already tick aligned.
Please provide a testcase (or detailed use-case) which proves that this is necessary.
tglx
> --- > > kernel/hrtimer.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > Index: linux-2.6-git/kernel/hrtimer.c > =================================================================== > --- linux-2.6-git.orig/kernel/hrtimer.c 2006-02-12 18:32:48.000000000 +0100 > +++ linux-2.6-git/kernel/hrtimer.c 2006-02-12 18:32:57.000000000 +0100 > @@ -419,7 +419,8 @@ hrtimer_start(struct hrtimer *timer, kti > new_base = switch_hrtimer_base(timer, base); > > if (mode == HRTIMER_REL) > - tim = ktime_add(tim, new_base->get_time()); > + tim = ktime_add(ktime_add(tim, new_base->get_time()), > + base->resolution); > timer->expires = tim; > > enqueue_hrtimer(timer, new_base);
- 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/
| |