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
prev parent reply other threads:[~2021-01-20 5:49 UTC|newest]
Thread overview: 11+ 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 14:14 ` Borislav Petkov
[not found] ` <20210116035251.GB29609@shbuild999.sh.intel.com>
2021-01-16 15:34 ` Paul E. McKenney
2021-01-16 16:09 ` Feng Tang
2021-01-19 4:27 ` Paul E. McKenney
2021-01-19 10:02 ` Borislav Petkov
2021-01-19 12:15 ` Feng Tang
2021-01-19 13:17 ` Borislav Petkov
2021-01-19 15:09 ` Feng Tang
2021-01-19 15:33 ` Borislav Petkov
2021-01-20 5:48 ` Feng Tang [this message]
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