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From: Ingo Molnar <mingo@elte.hu>
To: ling.ma@intel.com, Arjan van de Ven <arjan@infradead.org>,
	Dave Jones <davej@redhat.com>
Cc: hpa@zytor.com, tglx@linutronix.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] [X86] Compile Option Os versus O2 on latest x86 platform
Date: Thu, 26 Nov 2009 10:49:30 +0100	[thread overview]
Message-ID: <20091126094930.GD32275@elte.hu> (raw)
In-Reply-To: <1259222752-8161-1-git-send-email-ling.ma@intel.com>


* ling.ma@intel.com <ling.ma@intel.com> wrote:

> Benchmarks:                          improvement 
> volano                                8%
> netperf                               6.7% 
> tbench                                6.45%
> Kbuild                                5.5% (3 time test, average improvement)

that Kbuild result looks suspicious. A kbuild only uses 25% of system 
time, so an 5.5% improvement means that system utilization dropped from 
25% to 19.5%, a 28% improvement in the kernel! That looks rather 
unlikely.

Could you please post before/after 'perf stat --repeat 3' results so 
that we can see the noise level?

Thanks,

	Ingo

  reply	other threads:[~2009-11-26  9:49 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-26  8:05 [PATCH RFC] [X86] Compile Option Os versus O2 on latest x86 platform ling.ma
2009-11-26  9:49 ` Ingo Molnar [this message]
2009-12-01  8:54   ` Ma, Ling
2009-12-01 10:14     ` Arjan van de Ven
2009-12-01 16:11       ` H. Peter Anvin
2009-12-03 15:03       ` Ma, Ling
2009-12-03 15:05         ` H. Peter Anvin
2009-12-03 15:31           ` Ingo Molnar
2009-12-03 15:46             ` H. Peter Anvin
2009-12-02  9:47     ` Ingo Molnar

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