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From: Mel Gorman <mgorman@techsingularity.net>
To: Mike Galbraith <efault@gmx.de>
Cc: Barry Song <21cnbao@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Aubrey Li <aubrey.li@linux.intel.com>,
	Barry Song <song.bao.hua@hisilicon.com>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: wakeup_affine_weight() is b0rked - was Re: [PATCH 2/2] sched/fair: Scale wakeup granularity relative to nr_running
Date: Tue, 5 Oct 2021 08:47:19 +0100	[thread overview]
Message-ID: <20211005074719.GP3959@techsingularity.net> (raw)
In-Reply-To: <4f571c5c759b9d356d1bb4114fb169181194a780.camel@gmx.de>

On Mon, Oct 04, 2021 at 11:06:30AM +0200, Mike Galbraith wrote:
> On Mon, 2021-10-04 at 06:34 +0200, Mike Galbraith wrote:
> > On Sun, 2021-10-03 at 20:34 +1300, Barry Song wrote:
> > >
> > > I am wondering if this should be the responsibility of wake_wide()?
> >
> > Those event threads we stacked so high (which are kde minions btw),
> > don't generally accrue _any_ wakee_flips, so when X wakes a slew of the
> > things, wake_wide()'s heuristic rejects the lot.
> >
> > So yeah, the blame game for this issue is a target rich environment.
> > Shoot either of 'em (or both), and you'll hit the bad guy.
> 
> The mallet below convinced wake_wide() that X waking event threads is
> something it most definitely should care about.  It's not perfect, can
> get caught with its pants down, because behavior changes a LOT, but I
> at least have to work at it a bit to stack tasks to the ceiling.
> 
> With make -j8 running along with firefox with two tabs, one containing
> youtube's suggestions of stuff you probably don't want to watch, the
> other a running clip, if I have the idle tab in focus, and don't drive
> mouse around, flips decay enough for wake_wide() to lose interest, but
> just wiggle the mouse, and it starts waking wide. Focus on the running
> clip, and it continuously wakes wide.  
> 
> Hacky, but way better behavior.. at this particular testcase.. in this
> particular box.. at least once :)
> 

Only three machines managed to complete tests overnight. For most
workloads test, it was neutral or slight improvements. For
multi-kernbench__netperf-tcp-rr-multipair (kernel compile +
netperf-tcp-rr combined), there was little to no change.

For the heavy overloaded cases (hackbench again), it was variable. Worst
improvement was a gain of 1-3%. Best improvement (single socket skylake
with 8 logical CPUs SMT enabled) was 1%-18% depending on the group
count.

-- 
Mel Gorman
SUSE Labs

  reply	other threads:[~2021-10-05  7:47 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-20 14:26 [PATCH 0/2] Scale wakeup granularity relative to nr_running Mel Gorman
2021-09-20 14:26 ` [PATCH 1/2] sched/fair: Remove redundant lookup of rq in check_preempt_wakeup Mel Gorman
2021-09-21  7:21   ` Vincent Guittot
2021-09-21  7:53     ` Mel Gorman
2021-09-21  8:12       ` Vincent Guittot
2021-09-21  8:21       ` Peter Zijlstra
2021-09-21 10:03         ` Mel Gorman
2021-09-20 14:26 ` [PATCH 2/2] sched/fair: Scale wakeup granularity relative to nr_running Mel Gorman
2021-09-21  3:52   ` Mike Galbraith
2021-09-21  5:50     ` Mike Galbraith
2021-09-21  7:04     ` Mike Galbraith
2021-09-21 10:36     ` Mel Gorman
2021-09-21 12:32       ` Mike Galbraith
2021-09-21 14:03         ` Mel Gorman
2021-10-05  9:24         ` Peter Zijlstra
2021-09-22  5:22       ` Mike Galbraith
2021-09-22 13:20         ` Mel Gorman
2021-09-22 14:04           ` Mike Galbraith
2021-09-22 14:15           ` Vincent Guittot
2021-09-22 15:04             ` Mel Gorman
2021-09-22 16:00               ` Vincent Guittot
2021-09-22 17:38                 ` Mel Gorman
2021-09-22 18:22                   ` Vincent Guittot
2021-09-22 18:57                     ` Mel Gorman
2021-09-23  1:47                     ` Mike Galbraith
2021-09-23  8:40                       ` Vincent Guittot
2021-09-23  9:21                         ` Mike Galbraith
2021-09-23 12:41                           ` Vincent Guittot
2021-09-23 13:14                             ` Mike Galbraith
2021-09-27 11:17                             ` Mel Gorman
2021-09-27 14:17                               ` Mike Galbraith
2021-10-04  8:05                                 ` Mel Gorman
2021-10-04 16:37                                   ` Vincent Guittot
2021-10-05  7:41                                     ` Mel Gorman
2021-09-27 14:19                               ` Vincent Guittot
2021-09-27 15:02                                 ` Mel Gorman
2021-09-23 12:24                         ` Phil Auld
2021-10-05 10:36                           ` Peter Zijlstra
2021-10-05 14:12                             ` Phil Auld
2021-10-05 14:32                               ` Peter Zijlstra
2021-10-05 10:28                     ` Peter Zijlstra
2021-10-05 10:23                   ` Peter Zijlstra
2021-10-05  9:41               ` Peter Zijlstra
2021-09-22 15:05             ` Vincent Guittot
2021-10-05  9:32           ` Peter Zijlstra
2021-10-03  3:07         ` wakeup_affine_weight() is b0rked - was " Mike Galbraith
2021-10-03  7:34           ` Barry Song
2021-10-03 14:52             ` Mike Galbraith
2021-10-03 21:06               ` Barry Song
2021-10-04  1:49                 ` Mike Galbraith
2021-10-04  4:34             ` Mike Galbraith
2021-10-04  9:06               ` Mike Galbraith
2021-10-05  7:47                 ` Mel Gorman [this message]
2021-10-05  8:42                   ` Mike Galbraith
2021-10-05  9:31                     ` Mel Gorman
2021-10-06  6:46                       ` Mike Galbraith
2021-10-08  5:06                       ` Mike Galbraith
2021-09-21  8:03   ` Vincent Guittot
2021-09-21 10:45     ` Mel Gorman

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