21.02.2014, 16:44, "Juri Lelli" <juri.le...@gmail.com>: > On Fri, 21 Feb 2014 16:09:25 +0400 > Kirill Tkhai <tk...@yandex.ru> wrote: > >> 21.02.2014, 15:39, "Kirill Tkhai" <tk...@yandex.ru>: >>> 21.02.2014, 14:37, "Peter Zijlstra" <pet...@infradead.org>: >>>> On Thu, Feb 20, 2014 at 02:16:00AM +0400, Kirill Tkhai wrote: >>>>> Since deadline tasks share rt bandwidth, we must care about >>>>> bandwidth timer set. Otherwise rt_time may grow up to infinity >>>>> in update_curr_dl(), if there are no other available RT tasks >>>>> on top level bandwidth. >>>>> >>>>> I'm going to decide the problem the way below. Almost untested >>>>> because of I skipped almost all of recent patches which haveto be >>>>> applied from lkml. >>>>> >>>>> Please say, if I skipped anything in idea. Maybe better put >>>>> start_top_rt_bandwidth() into set_curr_task_dl()? >>>> How about we only increment rt_time when there's an RT bandwidth timer >>>> active? >>> This case RT and DL may eat all the time: >>> >>> -------------- time ------------------> >>> |RT's working |DL's working| >>> ---------------------------- >>> |rt_runtime | | >>> ---------------------------- >>> | rt_period | >>> >>> Or at least more, than it's allowed. >>> >>> It looks like, if we want to limit time of high priority classes >>> execution, we have to set the timer anyway. >> Oh, above is confusing. Sorry. >> >> I mean one RT task and >> >> ----------------- time --------------------------> >> |DL's working |RT's working| |DL's working | >> -------------------------------------------------- >> | |rt_runtime | | | >> -------------------------------------------------- >> | | rt_period | | >> >> In this case FAIR receives less ratio, than >> (rt_period-rt_runtime)/rt_period. > > DL tasks won't be allowed to run in this situation, as their bw exceedes > rt_runtime/rt_period.
Maybe, I don't uderstand. Where does DL control summary (DL+RT) runtime? RT does not do this too. But it looks like, RT has to do this. Kirill -- 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/
