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From: Borislav Petkov <bp@alien8.de>
To: Feng Tang <feng.tang@intel.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>,
	kernel test robot <oliver.sang@intel.com>,
	Jonathan Lemon <bsd@fb.com>, Tony Luck <tony.luck@intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	x86@kernel.org, lkp@lists.01.org, lkp@intel.com,
	ying.huang@intel.com, zhengjun.xing@intel.com
Subject: Re: [x86/mce]  7bb39313cd:  netperf.Throughput_tps -4.5% regression
Date: Tue, 19 Jan 2021 16:33:50 +0100	[thread overview]
Message-ID: <20210119153350.GM27433@zn.tnic> (raw)
In-Reply-To: <20210119150903.GA21908@shbuild999.sh.intel.com>

On Tue, Jan 19, 2021 at 11:09:03PM +0800, Feng Tang wrote:
> Yes, that can happen. I started a 4 tasks netperf on a 4C/8T KBL desktop,
> and also saw around 2% improvement. Both the kernel config and the
> platform matters.

Oh great. ;-\

> For the performance changes I have checked, sometimes the change can be
> reproduced on platforms of different generations (the exact delta number
> may differs), sometimes it can only be reproduced on one specific platform,
> like some old generation, or special one like Xeon Phi.

Probably because that Xeon Phi thing is not as powerful cache-wise as
some newer ones which have bigger caches and smarter hw prefetchers,
etc.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de>
To: lkp@lists.01.org
Subject: Re: [x86/mce] 7bb39313cd: netperf.Throughput_tps -4.5% regression
Date: Tue, 19 Jan 2021 16:33:50 +0100	[thread overview]
Message-ID: <20210119153350.GM27433@zn.tnic> (raw)
In-Reply-To: <20210119150903.GA21908@shbuild999.sh.intel.com>

[-- Attachment #1: Type: text/plain, Size: 775 bytes --]

On Tue, Jan 19, 2021 at 11:09:03PM +0800, Feng Tang wrote:
> Yes, that can happen. I started a 4 tasks netperf on a 4C/8T KBL desktop,
> and also saw around 2% improvement. Both the kernel config and the
> platform matters.

Oh great. ;-\

> For the performance changes I have checked, sometimes the change can be
> reproduced on platforms of different generations (the exact delta number
> may differs), sometimes it can only be reproduced on one specific platform,
> like some old generation, or special one like Xeon Phi.

Probably because that Xeon Phi thing is not as powerful cache-wise as
some newer ones which have bigger caches and smarter hw prefetchers,
etc.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2021-01-19 15:36 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-12 14:21 [x86/mce] 7bb39313cd: netperf.Throughput_tps -4.5% regression kernel test robot
2021-01-12 14:21 ` kernel test robot
2021-01-12 14:14 ` Borislav Petkov
2021-01-12 14:14   ` Borislav Petkov
     [not found]   ` <20210116035251.GB29609@shbuild999.sh.intel.com>
2021-01-16 15:34     ` Paul E. McKenney
2021-01-16 15:34       ` Paul E. McKenney
2021-01-16 16:09       ` Feng Tang
2021-01-16 16:09         ` Feng Tang
2021-01-19  4:27         ` Paul E. McKenney
2021-01-19  4:27           ` Paul E. McKenney
2021-01-19 10:02           ` Borislav Petkov
2021-01-19 10:02             ` Borislav Petkov
2021-01-19 12:15             ` Feng Tang
2021-01-19 12:15               ` Feng Tang
2021-01-19 13:17               ` Borislav Petkov
2021-01-19 13:17                 ` Borislav Petkov
2021-01-19 15:09                 ` Feng Tang
2021-01-19 15:09                   ` Feng Tang
2021-01-19 15:33                   ` Borislav Petkov [this message]
2021-01-19 15:33                     ` Borislav Petkov
2021-01-20  5:48                     ` Feng Tang
2021-01-20  5:48                       ` Feng Tang

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