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From: "Kleen, Andi" <andi.kleen@intel.com>
To: "Tang, Feng" <feng.tang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	"Chen, Rong A" <rong.a.chen@intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Ingo Molnar <mingo@kernel.org>,
	Vince Weaver <vincent.weaver@maine.edu>,
	Jiri Olsa <jolsa@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
	Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
	Stephane Eranian <eranian@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	"lkp@lists.01.org" <lkp@lists.01.org>,
	"Huang, Ying" <ying.huang@intel.com>
Subject: RE: [LKP] Re: [perf/x86] 81ec3f3c4c: will-it-scale.per_process_ops -5.5% regression
Date: Sat, 22 Feb 2020 17:08:20 +0000	[thread overview]
Message-ID: <E8ECBC65D0B2554DAD44EBE43059B3740F2241@ORSMSX110.amr.corp.intel.com> (raw)
In-Reply-To: <20200222124359.GA86836@shbuild999.sh.intel.com>

>Thanks for the suggestion, I tried this and the 5.5 regrssion is gone!
>which also confirms the offset for the bulk of stuff following "pmu"
>causes the performance drop.

Okay that confirms that it is false sharing. Looking at c2c is the right way to
go then.

Peter, could adopt the padding as a workaround for now?

-Andi

WARNING: multiple messages have this Message-ID (diff)
From: Kleen, Andi <andi.kleen@intel.com>
To: lkp@lists.01.org
Subject: Re: [perf/x86] 81ec3f3c4c: will-it-scale.per_process_ops -5.5% regression
Date: Sat, 22 Feb 2020 17:08:20 +0000	[thread overview]
Message-ID: <E8ECBC65D0B2554DAD44EBE43059B3740F2241@ORSMSX110.amr.corp.intel.com> (raw)
In-Reply-To: <20200222124359.GA86836@shbuild999.sh.intel.com>

[-- Attachment #1: Type: text/plain, Size: 334 bytes --]

>Thanks for the suggestion, I tried this and the 5.5 regrssion is gone!
>which also confirms the offset for the bulk of stuff following "pmu"
>causes the performance drop.

Okay that confirms that it is false sharing. Looking at c2c is the right way to
go then.

Peter, could adopt the padding as a workaround for now?

-Andi

  reply	other threads:[~2020-02-22 17:08 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-05 12:32 [perf/x86] 81ec3f3c4c: will-it-scale.per_process_ops -5.5% regression kernel test robot
2020-02-05 12:32 ` kernel test robot
2020-02-05 12:58 ` Peter Zijlstra
2020-02-05 12:58   ` Peter Zijlstra
2020-02-06  3:04   ` [LKP] " Li, Philip
2020-02-06  3:04     ` Li, Philip
2020-02-21  8:03   ` [LKP] " Feng Tang
2020-02-21  8:03     ` Feng Tang
2020-02-21 10:58     ` [LKP] " Peter Zijlstra
2020-02-21 10:58       ` Peter Zijlstra
2020-02-21 13:20     ` [LKP] " Jiri Olsa
2020-02-21 13:20       ` Jiri Olsa
2020-02-23 14:11       ` [LKP] " Feng Tang
2020-02-23 14:11         ` Feng Tang
2020-02-23 17:37         ` [LKP] " Linus Torvalds
2020-02-23 17:37           ` Linus Torvalds
2020-02-24  0:33           ` [LKP] " Feng Tang
2020-02-24  0:33             ` Feng Tang
2020-02-24  1:06             ` [LKP] " Linus Torvalds
2020-02-24  1:06               ` Linus Torvalds
2020-02-24  1:58               ` [LKP] " Huang, Ying
2020-02-24  1:58                 ` Huang, Ying
2020-02-24  2:19               ` [LKP] " Feng Tang
2020-02-24  2:19                 ` Feng Tang
2020-02-24 13:20                 ` [LKP] " Feng Tang
2020-02-24 13:20                   ` Feng Tang
2020-02-24 19:24                 ` [LKP] " Linus Torvalds
2020-02-24 19:24                   ` Linus Torvalds
2020-02-24 19:42                   ` [LKP] " Kleen, Andi
2020-02-24 19:42                     ` Kleen, Andi
2020-02-24 20:09                   ` [LKP] " Linus Torvalds
2020-02-24 20:09                     ` Linus Torvalds
2020-02-24 20:47                     ` [LKP] " Linus Torvalds
2020-02-24 20:47                       ` Linus Torvalds
2020-02-24 21:20                       ` [LKP] " Eric W. Biederman
2020-02-24 21:20                         ` Eric W. Biederman
2020-02-24 21:43                         ` [LKP] " Linus Torvalds
2020-02-24 21:43                           ` Linus Torvalds
2020-02-24 21:59                           ` [LKP] " Eric W. Biederman
2020-02-24 21:59                             ` Eric W. Biederman
2020-02-24 22:12                             ` [LKP] " Linus Torvalds
2020-02-24 22:12                               ` Linus Torvalds
2020-02-25  2:57                       ` [LKP] " Feng Tang
2020-02-25  2:57                         ` Feng Tang
2020-02-25  3:15                         ` [LKP] " Linus Torvalds
2020-02-25  3:15                           ` Linus Torvalds
2020-02-25  4:53                           ` [LKP] " Feng Tang
2020-02-25  4:53                             ` Feng Tang
2020-02-23 19:36         ` [LKP] " Jiri Olsa
2020-02-23 19:36           ` Jiri Olsa
2020-02-24  1:14           ` Feng Tang
2020-02-21 18:05     ` [LKP] " Kleen, Andi
2020-02-21 18:05       ` Kleen, Andi
2020-02-22 12:43       ` [LKP] " Feng Tang
2020-02-22 12:43         ` Feng Tang
2020-02-22 17:08         ` Kleen, Andi [this message]
2020-02-22 17:08           ` Kleen, Andi

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