From: Thomas Gleixner <tglx@linutronix.de>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Ye Xiaolong <xiaolong.ye@intel.com>, Russ Anderson <rja@sgi.com>,
Dimitri Sivanich <sivanich@sgi.com>,
Matt Fleming <matt@codeblueprint.co.uk>,
x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
Mike Travis <travis@sgi.com>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Alex Thorlton <athorlton@sgi.com>,
lkp@01.org
Subject: Re: [LKP] [lkp] [x86/platform/UV] 71854cb812: will-it-scale.per_thread_ops -2.3% regression
Date: Mon, 31 Oct 2016 12:19:16 -0600 (MDT) [thread overview]
Message-ID: <alpine.DEB.2.20.1610311216520.10522@nanos> (raw)
In-Reply-To: <20161031054101.b27mjyr46b3r2tbp@wfg-t540p.sh.intel.com>
On Mon, 31 Oct 2016, Fengguang Wu wrote:
> On Fri, Oct 28, 2016 at 12:37:45AM +0200, Thomas Gleixner wrote:
> > I have no explanation for this either, but you really should try to figure
> > out what's going on here.
>
> Xiaolong, how about doing a small debug patch (a WARN_ONCE() line may
> be enough) to verify whether the code path is executed?
>
> It'd also help to compare vmlinux according to Thomas' reasoning:
>
> > The only difference between plain rc1 and rc + this patch is the resulting
> > text size and therefor some other unrelated stuff moving to different
> > places in memory which has some yet to figure out side effects.
So one other thing you might try is using rc3 as a base line and then
revert the patch in question on top of rc3 and see whether that weird
behaviour persists.
> > From bisect POV, the below graphs show the user_time and system_time
> are clearly and consistently different before/after commit 71854cb812.
> So this commit must impacted something.
I agree. I just have no idea what happens.
Thanks,
tglx
prev parent reply other threads:[~2016-10-31 18:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-20 1:48 [PATCH v2] x86/platform/UV: Fix support for EFI_OLD_MEMMAP after BIOS callback updates Alex Thorlton
2016-10-20 12:26 ` Matt Fleming
2016-10-21 5:48 ` [tip:x86/urgent] " tip-bot for Alex Thorlton
2016-10-25 6:46 ` [lkp] [x86/platform/UV] 71854cb812: will-it-scale.per_thread_ops -2.3% regression kernel test robot
2016-10-25 10:57 ` Thomas Gleixner
2016-10-27 1:55 ` Ye Xiaolong
2016-10-27 22:37 ` Thomas Gleixner
2016-10-31 5:41 ` [LKP] " Fengguang Wu
2016-10-31 18:19 ` Thomas Gleixner [this message]
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