From: Feng Tang <feng.tang@intel.com>
To: lkp@lists.01.org
Subject: 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>
[-- Attachment #1: Type: text/plain, Size: 667 bytes --]
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
WARNING: multiple messages have this Message-ID (diff)
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
next prev parent reply other threads:[~2020-08-19 3:04 UTC|newest]
Thread overview: 50+ 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 11:44 ` kernel test robot
2020-04-25 13:01 ` Borislav Petkov
2020-04-25 13:01 ` Borislav Petkov
2020-08-18 8:29 ` Feng Tang
2020-08-18 8:29 ` [LKP] " Feng Tang
2020-08-18 20:06 ` Luck, Tony
2020-08-18 20:06 ` [LKP] " Luck, Tony
2020-08-19 2:04 ` Feng Tang
2020-08-19 2:04 ` [LKP] " Feng Tang
2020-08-19 2:23 ` Luck, Tony
2020-08-19 2:23 ` [LKP] " Luck, Tony
2020-08-19 3:04 ` Feng Tang [this message]
2020-08-19 3:04 ` Feng Tang
2020-08-19 3:15 ` Feng Tang
2020-08-19 3:15 ` [LKP] " Feng Tang
2020-08-21 2:02 ` Feng Tang
2020-08-21 2:02 ` [LKP] " Feng Tang
2020-08-24 15:14 ` Borislav Petkov
2020-08-24 15:14 ` [LKP] " Borislav Petkov
2020-08-24 15:33 ` Feng Tang
2020-08-24 15:33 ` [LKP] " Feng Tang
2020-08-24 15:38 ` Luck, Tony
2020-08-24 15:38 ` [LKP] " Luck, Tony
2020-08-24 15:48 ` Feng Tang
2020-08-24 15:48 ` [LKP] " Feng Tang
2020-08-24 16:12 ` Borislav Petkov
2020-08-24 16:12 ` [LKP] " Borislav Petkov
2020-08-24 16:56 ` Mel Gorman
2020-08-24 16:56 ` [LKP] " Mel Gorman
2020-08-25 6:49 ` Feng Tang
2020-08-25 6:49 ` [LKP] " Feng Tang
2020-08-25 6:23 ` Feng Tang
2020-08-25 6:23 ` [LKP] " Feng Tang
2020-08-25 16:44 ` Luck, Tony
2020-08-25 16:44 ` [LKP] " Luck, Tony
2020-08-26 1:45 ` Feng Tang
2020-08-26 1:45 ` [LKP] " Feng Tang
2020-08-28 17:48 ` Borislav Petkov
2020-08-28 17:48 ` [LKP] " Borislav Petkov
2020-08-31 2:16 ` Feng Tang
2020-08-31 2:16 ` [LKP] " Feng Tang
2020-08-31 7:56 ` Mel Gorman
2020-08-31 7:56 ` [LKP] " Mel Gorman
2020-08-31 8:23 ` Feng Tang
2020-08-31 8:23 ` [LKP] " Feng Tang
2020-08-31 8:55 ` Mel Gorman
2020-08-31 8:55 ` [LKP] " Mel Gorman
2020-08-31 12:53 ` Feng Tang
2020-08-31 12:53 ` [LKP] " Feng Tang
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