On Tue, 10 Nov 2015 17:36:46 +0100 Peter Zijlstra <[email protected]> wrote:
> > The downside is that we need to restart the timers every time if > > user were to change injection parameters, i.e. duration and percent. > > Or do locking which might be too expensive. In the previous > > approach, it will naturally catch up the parameter change. > > Why? the timer will fire and observe the new value for reprogramming > the next period. All you need to do is to ensure whole values are > written/read -- ie. avoid load/store tearing. Different per CPU timer may intercept parameter changes at slightly different time, so there is a race condition such that some CPUs may catch the period change later by one period, which results in a correct period change but at a different time, i.e. out of sync. Jacob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
