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From: "Kleen, Andi" <andi.kleen@intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	"Tang, Feng" <feng.tang@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"Chen, Rong A" <rong.a.chen@intel.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>,
	"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: Mon, 24 Feb 2020 19:42:45 +0000	[thread overview]
Message-ID: <E8ECBC65D0B2554DAD44EBE43059B3740F2AA1@ORSMSX110.amr.corp.intel.com> (raw)
In-Reply-To: <CAHk-=wjkSb1OkiCSn_fzf2v7A=K0bNsUEeQa+06XMhTO+oQUaA@mail.gmail.com>

>Does anybody else have any ideas?

We've had problems with atomics having strange ordering constraints before.

But it might be c2c missing the right cache line. There are some known cases where that can happen.

Feng, can you double check with 

perf record -a -d -e mem_load_l3_hit_retired.xsnp_hitm:pp,mem_load_l3_miss_retired.remote_hitm:pp ...

Does it report the same hot IPs as c2c?
What's the break down between the first and the second event for the hot IPs? The first is inside socket, the second between sockets.

-Andi


  reply	other threads:[~2020-02-24 19:42 UTC|newest]

Thread overview: 28+ 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 12:58 ` Peter Zijlstra
2020-02-06  3:04   ` [LKP] " Li, Philip
2020-02-21  8:03   ` Feng Tang
2020-02-21 10:58     ` Peter Zijlstra
2020-02-21 13:20     ` Jiri Olsa
2020-02-23 14:11       ` Feng Tang
2020-02-23 17:37         ` Linus Torvalds
2020-02-24  0:33           ` Feng Tang
2020-02-24  1:06             ` Linus Torvalds
2020-02-24  1:58               ` Huang, Ying
2020-02-24  2:19               ` Feng Tang
2020-02-24 13:20                 ` Feng Tang
2020-02-24 19:24                 ` Linus Torvalds
2020-02-24 19:42                   ` Kleen, Andi [this message]
2020-02-24 20:09                   ` Linus Torvalds
2020-02-24 20:47                     ` Linus Torvalds
2020-02-24 21:20                       ` Eric W. Biederman
2020-02-24 21:43                         ` Linus Torvalds
2020-02-24 21:59                           ` Eric W. Biederman
2020-02-24 22:12                             ` Linus Torvalds
2020-02-25  2:57                       ` Feng Tang
2020-02-25  3:15                         ` Linus Torvalds
2020-02-25  4:53                           ` Feng Tang
2020-02-23 19:36         ` Jiri Olsa
2020-02-21 18:05     ` Kleen, Andi
2020-02-22 12:43       ` Feng Tang
2020-02-22 17:08         ` Kleen, Andi

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