Messages in this thread | | | From | Vincent Guittot <> | Date | Mon, 12 Feb 2018 12:02:49 +0100 | Subject | Re: [PATCH v3 1/3] sched: Stop nohz stats when decayed |
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On 12 February 2018 at 11:45, Peter Zijlstra <peterz@infradead.org> wrote: > On Mon, Feb 12, 2018 at 09:07:52AM +0100, Vincent Guittot wrote: >> @@ -9383,11 +9450,16 @@ static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) >> * work being done for other cpus. Next load >> * balancing owner will pick it up. >> */ >> - if (need_resched()) >> - break; >> + if (need_resched()) { >> + has_blocked_load = true; >> + goto abort; >> + } >> >> rq = cpu_rq(balance_cpu); >> >> + update_blocked_averages(rq->cpu); > > Does that want to be update_nohz_stats() ?
I was about to say yesy but the test if (!time_after(jiffies, rq->last_blocked_load_update_tick)) worry me a bit because it can skip the update and the chance to clear nohz.has_blocked. As an example the tick is 10ms long on arm 32bits so we can easily reach the 32ms decay within the current tick even if we have already updated it
> >> + has_blocked_load |= rq->has_blocked_load; >> + >> /* >> * If time for next balance is due, >> * do the balance.
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