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Date:   Wed, 22 May 2019 22:12:18 +0800
From:   kernel test robot <rong.a.chen@intel.com>
To:     Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>, lkp@01.org
Subject: Re: [ubsan] f0996bc297: netperf.Throughput_total_tps -7.6% regression
Message-ID: <20190522141218.GI19312@shao2-debian>
References: <20190520053851.GY31424@shao2-debian>
 <4834add1-711e-b441-1956-1ab2b2d89353@virtuozzo.com>
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On Mon, May 20, 2019 at 12:50:30PM +0300, Andrey Ryabinin wrote:
> 
> 
> On 5/20/19 8:38 AM, kernel test robot wrote:
> > Greeting,
> > 
> > FYI, we noticed a -7.6% regression of netperf.Throughput_total_tps due to commit:
> > 
> > 
> > commit: f0996bc2978e02d2ea898101462b960f6119b18f ("ubsan: Fix nasty -Wbuiltin-declaration-mismatch GCC-9 warnings")
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> > 
> 
> This can't be right. First of all the commit makes changes only lib/ubsan.c which is compiled only when CONFIG_UBSAN=y.
> In your config:
> # CONFIG_UBSAN is not set 
> 
> But even in the case of enabled UBSAN that commit doesn't change the generated machine code at all.

Hi,

Sorry for bringing you inconvenience. We retested the commit and
couldn't reproduce the regression, please ignore the invalid report.

Best Regards,
Rong Chen