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From: Feng Tang <feng.tang@intel.com>
To: lkp@lists.01.org
Subject: Re: [x86/mce] 7bb39313cd: netperf.Throughput_tps -4.5% regression
Date: Wed, 20 Jan 2021 13:48:15 +0800	[thread overview]
Message-ID: <20210120054815.GA83476@shbuild999.sh.intel.com> (raw)
In-Reply-To: <20210119153350.GM27433@zn.tnic>

[-- Attachment #1: Type: text/plain, Size: 962 bytes --]

On Tue, Jan 19, 2021 at 04:33:50PM +0100, Borislav Petkov wrote:
> 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.

Yes, cache size/architecture/policy plays a critical role in these
benchmarking, which is our first thing to check for these strange
kernel performance changes.

Thanks,
Feng

WARNING: multiple messages have this Message-ID (diff)
From: Feng Tang <feng.tang@intel.com>
To: Borislav Petkov <bp@alien8.de>
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: Wed, 20 Jan 2021 13:48:15 +0800	[thread overview]
Message-ID: <20210120054815.GA83476@shbuild999.sh.intel.com> (raw)
In-Reply-To: <20210119153350.GM27433@zn.tnic>

On Tue, Jan 19, 2021 at 04:33:50PM +0100, Borislav Petkov wrote:
> 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.

Yes, cache size/architecture/policy plays a critical role in these
benchmarking, which is our first thing to check for these strange
kernel performance changes.

Thanks,
Feng

  reply	other threads:[~2021-01-20  5:48 UTC|newest]

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

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