On 09/09/2013 10:18 AM, Ronald Wahl wrote: > On 20.06.2013 17:00, Marc Kleine-Budde wrote: >> Hello Thomas, >> >> On 04/25/2013 04:53 PM, Marc Kleine-Budde wrote: >>> On 04/25/2013 04:21 PM, Thomas Gleixner wrote: >>>> On Tue, 23 Apr 2013, Marc Kleine-Budde wrote: >>>>> The commit >>>>> >>>>> 77cc982 clocksource: use clockevents_config_and_register() >>>>> where possible >>>>> >>>>> switches from manually calculating min_delta_ns (and others) and >>>>> clockevents_register_device() to automatic calculation via >>>>> clockevents_config_and_register(). During this conversation the "+ >>>>> 1" in >>>>> >>>>> min_delta_ns = clockevent_delta2ns(1, &clkevt.clkevt) + 1; >>>>> >>>>> was lost. This leads to problems with schedule_delayed_work() with >>>>> a delay of >>>>> "1". Resulting in the work not scheduled in time. >>>> >>>> Errm. How is schedule_delayed_work() related to this? > > I also stumbled over this issue now after upgrading from 3.4.57 to > 3.10.10. Even sleep() is unreliable - sleeping for 2 seconds often > sleeps just more than 3 seconds. > > The now lost +1 has actually been added in 2007 to solve a rounding issue: > > http://permalink.gmane.org/gmane.linux.kernel/549744 > > So I think this should either be fixed by always rounding up in > clockevent_delta2ns() or by adding +1 to the min_delta_ns in the > clockevents_config_and_register() function. Dunno if rounding up will > cause problems with the max_delta_ns as it might be too big then so > probably the second approach is better. > > Opinions?
Thomas, any thoughts on this? Marc -- Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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