From: Mike Galbraith <efault@gmx.de>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: 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: [PATCH 2/2] sched/fair: Scale wakeup granularity relative to nr_running
Date: Wed, 22 Sep 2021 16:04:01 +0200 [thread overview]
Message-ID: <97ee06c66fe0d900e3e0c4145ef9d33457ab3c65.camel@gmx.de> (raw)
In-Reply-To: <20210922132002.GX3959@techsingularity.net>
On Wed, 2021-09-22 at 14:20 +0100, Mel Gorman wrote:
> On Wed, Sep 22, 2021 at 07:22:20AM +0200, Mike Galbraith wrote:
> >
> > Watching 'while sleep 1; do clear;tail trace; done' with nothing but a
> > kbuild running is like watching top. There's enough stacking during
> > routine use of my desktop box that it runs into the tick granularity
> > wall pretty much continuously, so 'overload' may want redefining.
> >
>
> Ok, that's pretty convincing. You didn't mention if there were
> interactivity glitches but it's possible.
No, I didn't notice a thing. That's not surprising given the amount of
scheduling going on. The stack depth surprised me a bit though.
X-2230 [005] d..5. 2162.123029: wakeup_gran: runnable:6 wakee:QXcbEventQueue:2695 CPU5
X-2230 [005] d..5. 2162.123035: wakeup_gran: runnable:7 wakee:QXcbEventQueue:2656 CPU5
X-2230 [005] d..5. 2162.123046: wakeup_gran: runnable:8 wakee:QXcbEventQueue:5876 CPU5
X-2230 [005] d..5. 2162.123049: wakeup_gran: runnable:9 wakee:QXcbEventQueue:5355 CPU5
X-2230 [005] d..5. 2162.123083: wakeup_gran: runnable:10 wakee:QXcbEventQueue:2723 CPU5
X-2230 [005] d..5. 2162.123097: wakeup_gran: runnable:11 wakee:QXcbEventQueue:2630 CPU5
X-2230 [005] d..5. 2162.123208: wakeup_gran: runnable:12 wakee:QXcbEventQueue:2760 CPU5
That CPU# on the end is task_cpu(). Lord knows why X wakes all those,
but with no SD_BALANCE_WAKE, a busy box and all those having last lived
on waker's CPU, the resulting construct.. probably doesn't very closely
resemble what the programmer had in mind when threading.
-Mike
next prev parent reply other threads:[~2021-09-22 14:04 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-20 14:26 [PATCH 0/2] " 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 [this message]
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
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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