From: Anna-Maria Behnsen <anna-maria@linutronix.de>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
John Stultz <jstultz@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Eric Dumazet <edumazet@google.com>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Arjan van de Ven <arjan@infradead.org>,
"Paul E . McKenney" <paulmck@kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH v4 14/16] timer: Implement the hierarchical pull model
Date: Tue, 8 Nov 2022 18:02:11 +0100 (CET) [thread overview]
Message-ID: <9496e1a6-d1-1a20-c1c9-2bc3f34eb888@linutronix.de> (raw)
In-Reply-To: <20221108104738.GA21669@lothringen>
On Tue, 8 Nov 2022, Frederic Weisbecker wrote:
> On Fri, Nov 04, 2022 at 03:57:35PM +0100, Anna-Maria Behnsen wrote:
> > @@ -1859,6 +1863,36 @@ void forward_and_idle_timer_bases(unsigned long basej, u64 basem,
> > */
> > is_idle = time_after(nextevt, basej + 1);
> >
> > + if (is_idle) {
> > + u64 next_tmigr;
> > +
> > + next_tmigr = tmigr_cpu_deactivate(tevt->global);
> > +
> > + tevt->global = KTIME_MAX;
> > +
> > + /*
> > + * If CPU is the last going idle in timer migration
> > + * hierarchy, make sure CPU will wake up in time to handle
> > + * remote timers. next_tmigr == KTIME_MAX if other CPUs are
> > + * still active.
> > + */
> > + if (next_tmigr < tevt->local) {
> > + u64 tmp;
> > +
> > + /* If we missed a tick already, force 0 delta */
> > + if (next_tmigr < basem)
> > + next_tmigr = basem;
> > +
> > + tmp = div_u64(next_tmigr - basem, TICK_NSEC);
> > +
> > + nextevt = basej + (unsigned long)tmp;
> > + tevt->local = next_tmigr;
> > + is_idle = time_after(nextevt, basej + 1);
>
> So after that, tevt->global shouldn't matter anymore for tick_nohz_next_event(),
> right? If so then probably that line can go away (with a comment specifying why we can
> ignore the global part)?:
>
> tevt.local = min_t(u64, tevt.local, tevt.global);
>
tevt->global is set to KTIME_MAX anyway. So the whole tevt information is
also no longer required in tick_nohz_next_event(). I need to rework the
patch where this was introduced. Then the forward_and_idle_timer_bases()
could still simply return the next timer and then there is no longer a
point against using your idea with naming of the functions.
next prev parent reply other threads:[~2022-11-08 17:02 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-04 14:57 [PATCH v4 00/16] timer: Move from a push remote at enqueue to a pull at expiry model Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 01/16] tick-sched: Warn when next tick seems to be in the past Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 02/16] timer: Move store of next event into __next_timer_interrupt() Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 03/16] timer: Split next timer interrupt logic Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 04/16] timer: Rework idle logic Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 05/16] add_timer_on(): Make sure callers have TIMER_PINNED flag Anna-Maria Behnsen
2022-11-04 16:43 ` Frederic Weisbecker
2022-11-07 8:11 ` Anna-Maria Behnsen
2022-11-07 10:11 ` Frederic Weisbecker
2022-11-04 14:57 ` [PATCH v4 06/16] timer: Keep the pinned timers separate from the others Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 07/16] timer: Retrieve next expiry of pinned/non-pinned timers seperately Anna-Maria Behnsen
2022-11-07 11:58 ` Frederic Weisbecker
2022-11-04 14:57 ` [PATCH v4 08/16] timer: Rename get_next_timer_interrupt() Anna-Maria Behnsen
2022-11-07 12:13 ` Frederic Weisbecker
2022-11-04 14:57 ` [PATCH v4 09/16] timer: Split out "get next timer interrupt" functionality Anna-Maria Behnsen
2022-11-07 12:42 ` Frederic Weisbecker
2022-11-08 15:30 ` Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 10/16] timer: Add get next timer interrupt functionality for remote CPUs Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 11/16] timer: Restructure internal locking Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 12/16] timer: Check if timers base is handled already Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 13/16] tick/sched: Split out jiffies update helper function Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 14/16] timer: Implement the hierarchical pull model Anna-Maria Behnsen
2022-11-07 22:07 ` Frederic Weisbecker
2022-11-08 16:16 ` Anna-Maria Behnsen
2022-11-09 17:12 ` Frederic Weisbecker
2022-11-08 10:47 ` Frederic Weisbecker
2022-11-08 17:02 ` Anna-Maria Behnsen [this message]
2022-11-09 17:13 ` Frederic Weisbecker
2022-11-08 11:48 ` Frederic Weisbecker
2022-11-09 16:39 ` Frederic Weisbecker
2022-11-10 6:34 ` Anna-Maria Behnsen
2022-11-14 13:09 ` Frederic Weisbecker
2022-11-15 11:31 ` Frederic Weisbecker
2022-11-24 7:47 ` Anna-Maria Behnsen
2022-11-28 16:20 ` Frederic Weisbecker
2022-11-29 10:30 ` Frederic Weisbecker
2022-11-16 13:40 ` Frederic Weisbecker
2022-11-04 14:57 ` [PATCH v4 15/16] timer_migration: Add tracepoints Anna-Maria Behnsen
2022-11-04 14:57 ` [PATCH v4 16/16] timer: Always queue timers on the local CPU Anna-Maria Behnsen
2022-11-08 4:37 ` [PATCH v4 00/16] timer: Move from a push remote at enqueue to a pull at expiry model Pavan Kondeti
2022-11-08 15:06 ` Anna-Maria Behnsen
2022-11-08 16:04 ` Pavan Kondeti
2022-11-08 17:39 ` Anna-Maria Behnsen
2022-11-08 18:48 ` Pavan Kondeti
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