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From: Mel Gorman <mgorman@techsingularity.net>
To: Jirka Hladky <jhladky@redhat.com>
Cc: Phil Auld <pauld@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Hillf Danton <hdanton@sina.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Douglas Shakshober <dshaks@redhat.com>,
	Waiman Long <longman@redhat.com>, Joe Mario <jmario@redhat.com>,
	Bill Gray <bgray@redhat.com>
Subject: Re: [PATCH 00/13] Reconcile NUMA balancing decisions with the load balancer v6
Date: Fri, 8 May 2020 10:22:12 +0100	[thread overview]
Message-ID: <20200508092212.GE3758@techsingularity.net> (raw)
In-Reply-To: <CAE4VaGCDTeE16nNmSS8fGzCBvHsO=qkJAW6yDiORAxgsPi-Ziw@mail.gmail.com>

On Thu, May 07, 2020 at 06:29:44PM +0200, Jirka Hladky wrote:
> Hi Mel,
> 
> we are not targeting just OMP applications. We see the performance
> degradation also for other workloads, like SPECjbb2005 and
> SPECjvm2008. Even worse, it also affects a higher number of threads.
> For example, comparing 5.7.0-0.rc2 against 5.6 kernel, on 4 NUMA
> server with 2x AMD 7351 CPU, we see performance degradation 22% for 32
> threads (the system has 64 CPUs in total). We observe this degradation
> only when we run a single SPECjbb binary. When running 4 SPECjbb
> binaries in parallel, there is no change in performance between 5.6
> and 5.7.
> 

Minimally I suggest confirming that it's really due to
adjust_numa_imbalance() by making the function a no-op and retesting.
I have found odd artifacts with it but I'm unsure how to proceed without
causing problems elsehwere.

For example, netperf on localhost in some cases reported a regression
when the client and server were running on the same node. The problem
appears to be that netserver completes its work faster when running
local and goes idle more regularly. The cost of going idle and waking up
builds up and a lower throughput is reported but I'm not sure if gaming
an artifact like that is a good idea.

> That's why we are asking for the kernel tunable, which we would add to
> the tuned profile. We don't expect users to change this frequently but
> rather to set the performance profile once based on the purpose of the
> server.
> 
> If you could prepare a patch for us, we would be more than happy to
> test it extensively. Based on the results, we can then evaluate if
> it's the way to go. Thoughts?
> 

I would suggest simply disabling that function first to ensure that is
really what is causing problems for you.

-- 
Mel Gorman
SUSE Labs

  parent reply	other threads:[~2020-05-08  9:22 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24  9:52 [PATCH 00/13] Reconcile NUMA balancing decisions with the load balancer v6 Mel Gorman
2020-02-24  9:52 ` [PATCH 01/13] sched/fair: Allow a per-CPU kthread waking a task to stack on the same CPU, to fix XFS performance regression Mel Gorman
2020-02-24  9:52 ` [PATCH 02/13] sched/numa: Trace when no candidate CPU was found on the preferred node Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-02-24  9:52 ` [PATCH 03/13] sched/numa: Distinguish between the different task_numa_migrate failure cases Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] sched/numa: Distinguish between the different task_numa_migrate() " tip-bot2 for Mel Gorman
2020-02-24  9:52 ` [PATCH 04/13] sched/fair: Reorder enqueue/dequeue_task_fair path Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24  9:52 ` [PATCH 05/13] sched/numa: Replace runnable_load_avg by load_avg Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24  9:52 ` [PATCH 06/13] sched/numa: Use similar logic to the load balancer for moving between domains with spare capacity Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-02-24  9:52 ` [PATCH 07/13] sched/pelt: Remove unused runnable load average Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24  9:52 ` [PATCH 08/13] sched/pelt: Add a new runnable average signal Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24 16:01     ` Valentin Schneider
2020-02-24 16:34       ` Mel Gorman
2020-02-25  8:23       ` Vincent Guittot
2020-02-24  9:52 ` [PATCH 09/13] sched/fair: Take into account runnable_avg to classify group Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24  9:52 ` [PATCH 10/13] sched/numa: Prefer using an idle cpu as a migration target instead of comparing tasks Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] sched/numa: Prefer using an idle CPU " tip-bot2 for Mel Gorman
2020-02-24  9:52 ` [PATCH 11/13] sched/numa: Find an alternative idle CPU if the CPU is part of an active NUMA balance Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-02-24  9:52 ` [PATCH 12/13] sched/numa: Bias swapping tasks based on their preferred node Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-02-24  9:52 ` [PATCH 13/13] sched/numa: Stop an exhastive search if a reasonable swap candidate or idle CPU is found Mel Gorman
2020-02-24 15:20   ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-02-24 15:16 ` [PATCH 00/13] Reconcile NUMA balancing decisions with the load balancer v6 Ingo Molnar
2020-02-25 11:59   ` Mel Gorman
2020-02-25 13:28     ` Vincent Guittot
2020-02-25 14:24       ` Mel Gorman
2020-02-25 14:53         ` Vincent Guittot
2020-02-27  9:09         ` Ingo Molnar
2020-03-09 19:12 ` Phil Auld
2020-03-09 20:36   ` Mel Gorman
2020-03-12  9:54     ` Mel Gorman
2020-03-12 12:17       ` Jirka Hladky
     [not found]       ` <CAE4VaGA4q4_qfC5qe3zaLRfiJhvMaSb2WADgOcQeTwmPvNat+A@mail.gmail.com>
2020-03-12 15:56         ` Mel Gorman
2020-03-12 17:06           ` Jirka Hladky
     [not found]           ` <CAE4VaGD8DUEi6JnKd8vrqUL_8HZXnNyHMoK2D+1-F5wo+5Z53Q@mail.gmail.com>
2020-03-12 21:47             ` Mel Gorman
2020-03-12 22:24               ` Jirka Hladky
2020-03-20 15:08                 ` Jirka Hladky
     [not found]                 ` <CAE4VaGC09OfU2zXeq2yp_N0zXMbTku5ETz0KEocGi-RSiKXv-w@mail.gmail.com>
2020-03-20 15:22                   ` Mel Gorman
2020-03-20 15:33                     ` Jirka Hladky
     [not found]                     ` <CAE4VaGBGbTT8dqNyLWAwuiqL8E+3p1_SqP6XTTV71wNZMjc9Zg@mail.gmail.com>
2020-03-20 16:38                       ` Mel Gorman
2020-03-20 17:21                         ` Jirka Hladky
2020-05-07 15:24                         ` Jirka Hladky
2020-05-07 15:54                           ` Mel Gorman
2020-05-07 16:29                             ` Jirka Hladky
2020-05-07 17:49                               ` Phil Auld
     [not found]                                 ` <20200508034741.13036-1-hdanton@sina.com>
2020-05-18 14:52                                   ` Jirka Hladky
     [not found]                                     ` <20200519043154.10876-1-hdanton@sina.com>
2020-05-20 13:58                                       ` Jirka Hladky
2020-05-20 16:01                                         ` Jirka Hladky
2020-05-21 11:06                                         ` Mel Gorman
     [not found]                                         ` <20200521140931.15232-1-hdanton@sina.com>
2020-05-21 16:04                                           ` Mel Gorman
     [not found]                                           ` <20200522010950.3336-1-hdanton@sina.com>
2020-05-22 11:05                                             ` Mel Gorman
2020-05-08  9:22                               ` Mel Gorman [this message]
2020-05-08 11:05                                 ` Jirka Hladky
     [not found]                                 ` <CAE4VaGC_v6On-YvqdTwAWu3Mq4ofiV0pLov-QpV+QHr_SJr+Rw@mail.gmail.com>
2020-05-13 14:57                                   ` Jirka Hladky
2020-05-13 15:30                                     ` Mel Gorman
2020-05-13 16:20                                       ` Jirka Hladky
2020-05-14  9:50                                         ` Mel Gorman
     [not found]                                           ` <CAE4VaGCGUFOAZ+YHDnmeJ95o4W0j04Yb7EWnf8a43caUQs_WuQ@mail.gmail.com>
2020-05-14 10:08                                             ` Mel Gorman
2020-05-14 10:22                                               ` Jirka Hladky
2020-05-14 11:50                                                 ` Mel Gorman
2020-05-14 13:34                                                   ` Jirka Hladky
2020-05-14 15:31                                       ` Peter Zijlstra
2020-05-15  8:47                                         ` Mel Gorman
2020-05-15 11:17                                           ` Peter Zijlstra
2020-05-15 13:03                                             ` Mel Gorman
2020-05-15 13:12                                               ` Peter Zijlstra
2020-05-15 13:28                                                 ` Peter Zijlstra
2020-05-15 14:24                                             ` Peter Zijlstra
2020-05-21 10:38                                               ` Mel Gorman
2020-05-21 11:41                                                 ` Peter Zijlstra
2020-05-22 13:28                                                   ` Mel Gorman
2020-05-22 14:38                                                     ` Peter Zijlstra
2020-05-15 11:28                                           ` Peter Zijlstra
2020-05-15 12:22                                             ` Mel Gorman
2020-05-15 12:51                                               ` Peter Zijlstra
2020-05-15 14:43                                       ` Jirka Hladky

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