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Date:   Thu, 6 Aug 2020 15:34:52 +0200
From:   Ingo Molnar <mingo@kernel.org>
To:     kernel test robot <rong.a.chen@intel.com>,
        Dan Williams <dan.j.williams@intel.com>
Cc:     Dan Williams <dan.j.williams@intel.com>, tglx@linutronix.de,
        mingo@redhat.com, vishal.l.verma@intel.com, x86@kernel.org,
        stable@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
        Vivek Goyal <vgoyal@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Tony Luck <tony.luck@intel.com>,
        Erwin Tsaur <erwin.tsaur@intel.com>, linux-nvdimm@lists.01.org,
        linux-kernel@vger.kernel.org, 0day robot <lkp@intel.com>,
        lkp@lists.01.org
Subject: Re: [x86/copy_mc] a0ac629ebe: fio.read_iops -43.3% regression
Message-ID: <20200806133452.GA2077191@gmail.com>
References: <159630256804.3143511.8894023468833792004.stgit@dwillia2-desk3.amr.corp.intel.com>
 <20200803094257.GA23458@shao2-debian>
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* kernel test robot <rong.a.chen@intel.com> wrote:

> Greeting,
> 
> FYI, we noticed a -43.3% regression of fio.read_iops due to commit:
> 
> 
> commit: a0ac629ebe7b3d248cb93807782a00d9142fdb98 ("x86/copy_mc: Introduce copy_mc_generic()")
> url: https://github.com/0day-ci/linux/commits/Dan-Williams/Renovate-memcpy_mcsafe-with-copy_mc_to_-user-kernel/20200802-014046
> 
> 
> in testcase: fio-basic
> on test machine: 96 threads Intel(R) Xeon(R) Gold 6252 CPU @ 2.10GHz with 256G memory
> with following parameters:

So this performance regression, if it isn't a spurious result, looks 
concerning. Is this expected?

Thanks,

	Ingo