On 28-10-15, 07:28, Rafael J. Wysocki wrote: > Your argument seems to be that it should be OK to do the > cancel_delayed_work_sync()/gov_queue_work() combo in all cases, because > even if the new rate is greater than the old one, the user may actually > want it to take effect immediately and it shouldn't hurt to skip the next > sample anyway in that case. > > Is this really the case, though? What about the old rate is 1s, the new one > is 2s and the timer is just about to expire? Won't the canceling effectively > move the next sample 3s away from the previous one which may not be desirable? > > The current code just allows the timer to expire, unless that would prevent > the new rate from taking effect for too long, which seems perfectly reasonable > to me.
Okay, what about this case: old rate is 1s, new rate it 5s and we have just serviced the timer. With the current code we will receive evaluate again after 1 second instead of 5. Is that desirable ? I didn't wanted to keep special code for such corner cases. And then how many times are we going to update sampling rates ? But if we want to do something special, then we may schedule the work for following delay: delay = shared->time_stamp + new_sampling_rate. shared->time_stamp is the last time we evaluated the load. With this, we will be at shoot at the exact requested time, relative to the last time we evaluated the loads. -- viresh -- 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/
