On Sat, Jul 28, 2012 at 12:23:05AM +0200, Linus Walleij wrote: > On Tue, Jul 24, 2012 at 11:16 AM, Bedia, Vaibhav <vaibhav.be...@ti.com> wrote: > > >> > A connecting theme is that of being avle to flag clock sources as > >> > sched_clock providers. If all clocksources were tagged with > >> > rating, and only clocksources were used for sched_clock(), the > >> > kernel could select the highest-rated clock under all circumstances. > >> > > >> > But that's quite intrusive, more of an idea. :-P > >> > > > > Too intrusive I guess ;) > > > > There were some discussions on this in the context of AM335x [1] [2]. > > Right now only sched_clock can be registered and I guess this restriction > > is not going to go away any time soon. > > Why do you think that? The restriction to only assign sched_clock() at > compile-time was recently removed so its now runtime assigned. > > So yes, a clock source that can die and change frequency is no good > as primary system time, but the abstraction could still be used for > those that do, just add another flag NOT_CONTINUOUS or so, and > make sure the system does not select this for primary system > clock source. > > Then modelling sched_clock() on clock sources makes all more > sense: just select the best one. For primary system clock source, > do not select one which is non-continous.
Except for the overhead. sched_clock() is supposed to be as _fast_ as it can possibly be, because it has a direct impact on the performance of the system. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
