From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Eric Dumazet <edumazet@google.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Chris Mason <clm@fb.com>, Arjan van de Ven <arjan@infradead.org>,
rt@linutronix.de, Rik van Riel <riel@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
George Spelvin <linux@sciencehorizons.net>,
Len Brown <lenb@kernel.org>
Subject: Re: [patch V2 00/20] timer: Refactor the timer wheel
Date: Mon, 20 Jun 2016 08:41:47 -0700 [thread overview]
Message-ID: <20160620154146.GS3923@linux.vnet.ibm.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1606201712470.5839@nanos>
On Mon, Jun 20, 2016 at 05:13:41PM +0200, Thomas Gleixner wrote:
> On Mon, 20 Jun 2016, Paul E. McKenney wrote:
>
> > On Fri, Jun 17, 2016 at 01:26:28PM -0000, Thomas Gleixner wrote:
> > > This is the second version of the timer wheel rework series. The first series
> > > can be found here:
> > >
> > > http://lkml.kernel.org/r/20160613070440.950649741@linutronix.de
> > >
> > > The series is also available in git:
> > >
> > > git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git WIP.timers
> >
> > Ran some longer rcutorture tests, and the scripting complained about
> > hangs. This turned out to be due to the 12.5% uncertainty, so I fixed
>
> Is that stuff so sensitive? I'm surprised, because the old slack stuff got you
> 6.25% already.
But didn't you have to ask for slack?
Anyway, rcutorture allows three minutes longer than the duration, and
then kills the test (unless it is actively dumping the ftrace buffer).
A 30-minute test does fine either way, but a 60-minute test gets killed
with high probability. Changing to hrtimers makes things work nicely
(other than SRCU), even for 60-minute runs. I have run ten-hour
rcutorture runs with normal completion with the old timers.
Might well be that this switch to hrtimer is needed in some situations
for the old setup. Given that it happens only once per run, it clearly
has little or no performance downside, so I am queueing it regardless.
Well, I will do so once I take care of the arithmetic limitations that
are causing link-time errors on 32-bit systems.
Thanx, Paul
next prev parent reply other threads:[~2016-06-20 15:42 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-17 13:26 [patch V2 00/20] timer: Refactor the timer wheel Thomas Gleixner
2016-06-17 13:26 ` [patch V2 01/20] timer: Make pinned a timer property Thomas Gleixner
2016-06-17 13:26 ` [patch V2 02/20] x86/apic/uv: Initialize timer as pinned Thomas Gleixner
2016-06-17 13:26 ` [patch V2 03/20] x86/mce: " Thomas Gleixner
2016-06-17 13:26 ` [patch V2 05/20] driver/net/ethernet/tile: " Thomas Gleixner
2016-06-21 18:14 ` Peter Zijlstra
2016-06-17 13:26 ` [patch V2 04/20] cpufreq/powernv: " Thomas Gleixner
2016-06-17 13:26 ` [patch V2 06/20] drivers/tty/metag_da: " Thomas Gleixner
2016-06-17 13:26 ` [patch V2 07/20] drivers/tty/mips_ejtag: " Thomas Gleixner
2016-06-17 13:26 ` [patch V2 08/20] net/ipv4/inet: Initialize timers " Thomas Gleixner
2016-06-17 13:26 ` [patch V2 09/20] timer: Remove mod_timer_pinned Thomas Gleixner
2016-06-17 13:26 ` [patch V2 10/20] hlist: Add hlist_is_singular_node() helper Thomas Gleixner
2016-06-17 13:26 ` [patch V2 11/20] timer: Give a few structs and members proper names Thomas Gleixner
2016-06-17 13:26 ` [patch V2 12/20] timer: Switch to a non cascading wheel Thomas Gleixner
2016-06-18 9:55 ` George Spelvin
2016-06-24 10:06 ` Thomas Gleixner
2016-06-17 13:26 ` [patch V2 13/20] timer: Remove slack leftovers Thomas Gleixner
2016-06-17 13:26 ` [patch V2 14/20] timer: Move __run_timers() function Thomas Gleixner
2016-06-17 13:26 ` [patch V2 15/20] timer: Optimize collect timers for NOHZ Thomas Gleixner
2016-06-17 13:26 ` [patch V2 16/20] tick/sched: Remove pointless empty function Thomas Gleixner
2016-06-17 13:26 ` [patch V2 17/20] timer: Forward wheel clock whenever possible Thomas Gleixner
2016-06-17 13:26 ` [patch V2 18/20] timer: Only wake softirq if necessary Thomas Gleixner
2016-06-17 13:26 ` [patch V2 19/20] timer: Split out index calculation Thomas Gleixner
2016-06-17 13:26 ` [patch V2 20/20] timer: Optimization for same expiry time in mod_timer() Thomas Gleixner
2016-06-17 13:48 ` [patch V2 00/20] timer: Refactor the timer wheel Eric Dumazet
2016-06-17 13:57 ` Thomas Gleixner
2016-06-17 14:25 ` Eric Dumazet
2016-06-20 13:56 ` Thomas Gleixner
2016-06-20 14:46 ` Arjan van de Ven
2016-06-20 14:46 ` Thomas Gleixner
2016-06-20 14:49 ` Arjan van de Ven
2016-06-20 19:03 ` Rik van Riel
2016-06-21 2:48 ` Eric Dumazet
2016-06-17 14:26 ` Arjan van de Ven
2016-06-20 15:05 ` Paul E. McKenney
2016-06-20 15:13 ` Thomas Gleixner
2016-06-20 15:41 ` Paul E. McKenney [this message]
2016-06-22 7:37 ` Mike Galbraith
2016-06-22 8:44 ` Thomas Gleixner
2016-06-22 9:06 ` Mike Galbraith
2016-06-22 13:37 ` Mike Galbraith
2016-06-22 10:28 ` [LTP] " Cyril Hrubis
2016-06-23 8:27 ` Thomas Gleixner
2016-06-23 11:47 ` Cyril Hrubis
2016-06-23 13:58 ` George Spelvin
2016-06-23 14:10 ` Thomas Gleixner
2016-06-23 15:11 ` Cyril Hrubis
2016-06-23 15:21 ` Thomas Gleixner
2016-06-23 16:31 ` Cyril Hrubis
2016-06-26 19:00 ` Pavel Machek
2016-06-26 19:21 ` Arjan van de Ven
2016-06-26 20:02 ` Pavel Machek
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