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Date: Thu, 18 Aug 2016 05:45:13 +0200
From: Borislav Petkov <bp@suse.de>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Denys Vlasenko <dvlasenk@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>, Brian Gerst <brgerst@gmail.com>,
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        Andy Lutomirski <luto@amacapital.net>, lkp@01.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Ville =?utf-8?B?U3lyasOkbMOk?= <ville.syrjala@linux.intel.com>
Subject: Re: [LKP] [lkp] [x86/hweight] 65ea11ec6a:
 will-it-scale.per_process_ops 9.3% improvement
Message-ID: <20160818034513.GA21415@nazgul.tnic>
References: <20160816142642.GA24206@yexl-desktop>
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On Wed, Aug 17, 2016 at 03:29:04PM -0700, Huang, Ying wrote:
> branch-miss-rate decreased from ~0.30% to ~0.043%.
> 
> So I guess there are some code alignment change, which caused decreased
> branch miss rate.

Hrrm, I still can't imagine how that would happen if the machine
supports POPCNT and we never call the __sw_hweight* variants. Or does
it?

Can you paste /proc/cpuinfo from that Sandy Bridge-EP box?

Thanks.

-- 
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    Boris.

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