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From: Feng Tang <feng.tang@intel.com>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Borislav Petkov <bp@suse.de>,
	"Chen, Rong A" <rong.a.chen@intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"lkp@lists.01.org" <lkp@lists.01.org>
Subject: Re: [LKP] Re: [x86/mce] 1de08dccd3: will-it-scale.per_process_ops -14.1% regression
Date: Wed, 19 Aug 2020 11:04:02 +0800	[thread overview]
Message-ID: <20200819030402.GA7840@feng-iot> (raw)
In-Reply-To: <149e0cfb5b7e48dfb9bea966c7741336@intel.com>

On Wed, Aug 19, 2020 at 10:23:11AM +0800, Luck, Tony wrote:
> 	0000000000019260 D pqr_state
> 
> Do you have /sys/fs/resctrl mounted?  This variable is read on every context switch.
> If your benchmark does a lot of context switching and this now shares a cache line
> with something different (especially something that is sometimes modified from another
> CPU) that could cause some cache line bouncing.

No, the kernel doesn't has /sys/fs/resctrl mounted.

And the test case is not context switch intensive. It just forks a task
for each CPU which loops running malloc/free and counts the number of
complted operations for 300 seconds.

Thanks,
Feng

  reply	other threads:[~2020-08-19  3:21 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-25 11:44 [x86/mce] 1de08dccd3: will-it-scale.per_process_ops -14.1% regression kernel test robot
2020-04-25 13:01 ` Borislav Petkov
2020-08-18  8:29   ` [LKP] " Feng Tang
2020-08-18 20:06     ` Luck, Tony
2020-08-19  2:04       ` Feng Tang
2020-08-19  2:23         ` Luck, Tony
2020-08-19  3:04           ` Feng Tang [this message]
2020-08-19  3:15           ` Feng Tang
2020-08-21  2:02         ` Feng Tang
2020-08-24 15:14           ` Borislav Petkov
2020-08-24 15:33             ` Feng Tang
2020-08-24 15:38               ` Luck, Tony
2020-08-24 15:48                 ` Feng Tang
2020-08-24 16:12               ` Borislav Petkov
2020-08-24 16:56                 ` Mel Gorman
2020-08-25  6:49                   ` Feng Tang
2020-08-25  6:23                 ` Feng Tang
2020-08-25 16:44                   ` Luck, Tony
2020-08-26  1:45                     ` Feng Tang
2020-08-28 17:48                   ` Borislav Petkov
2020-08-31  2:16                     ` Feng Tang
2020-08-31  7:56                       ` Mel Gorman
2020-08-31  8:23                         ` Feng Tang
2020-08-31  8:55                           ` Mel Gorman
2020-08-31 12:53                             ` Feng Tang

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