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Message-ID: <D7C42C27E6CB1E4D8CBDF2F81EA92A260345A63FAC@azsmsx501.amr.corp.intel.com>
Date: Wed, 29 Apr 2009 09:00:29 -0700
From: "Styner, Douglas W" <douglas.w.styner@...el.com>
To: Andi Kleen <andi@...stfloor.org>,
Andrew Morton <akpm@...ux-foundation.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"Tripathi, Sharad C" <sharad.c.tripathi@...el.com>,
"arjan@...ux.intel.com" <arjan@...ux.intel.com>,
"Wilcox, Matthew R" <matthew.r.wilcox@...el.com>,
"Kleen, Andi" <andi.kleen@...el.com>,
"Siddha, Suresh B" <suresh.b.siddha@...el.com>,
"Ma, Chinang" <chinang.ma@...el.com>,
"Wang, Peter Xihong" <peter.xihong.wang@...el.com>,
"Nueckel, Hubert" <hubert.nueckel@...el.com>,
"Recalde, Luis F" <luis.f.recalde@...el.com>,
"Nelson, Doug" <doug.nelson@...el.com>,
"Cheng, Wu-sun" <wu-sun.cheng@...el.com>,
"Prickett, Terry O" <terry.o.prickett@...el.com>,
"Shunmuganathan, Rajalakshmi" <rajalakshmi.shunmuganathan@...el.com>,
"Garg, Anil K" <anil.k.garg@...el.com>,
"Chilukuri, Harita" <harita.chilukuri@...el.com>,
"chris.mason@...cle.com" <chris.mason@...cle.com>
Subject: RE: Mainline kernel OLTP performance update
What we showed was that vmstat and vtune agreed wrt system/user time. Oprofile is off by ~4% (4% too low for user. 4% too high for system)
>-----Original Message-----
>From: Andi Kleen [mailto:andi@...stfloor.org]
>Sent: Wednesday, April 29, 2009 1:28 AM
>To: Andrew Morton
>Cc: Styner, Douglas W; linux-kernel@...r.kernel.org; Tripathi, Sharad C;
>arjan@...ux.intel.com; Wilcox, Matthew R; Kleen, Andi; Siddha, Suresh B;
>Ma, Chinang; Wang, Peter Xihong; Nueckel, Hubert; Recalde, Luis F; Nelson,
>Doug; Cheng, Wu-sun; Prickett, Terry O; Shunmuganathan, Rajalakshmi; Garg,
>Anil K; Chilukuri, Harita; chris.mason@...cle.com
>Subject: Re: Mainline kernel OLTP performance update
>
>Andrew Morton <akpm@...ux-foundation.org> writes:
>
>>> ======oprofile CPU_CLK_UNHALTED for top 30 functions
>>> Cycles% 2.6.24.2 Cycles% 2.6.30-rc3
>>> 74.8578 <database> 69.1925 <database>
>>
>> ouch, that's a large drop in userspace CPU occupancy. It seems
>> inconsistent with the 1.91% above.
>
>That was determined to be an oprofile artifact/regression (see Doug's
>other email+thread) The 2.6.30 oprofile seems to be less accurate than
>the one in 2.6.24. Of course the question is if it can't get
>the user space right, is the kernel data accurate. But I believe
>Doug verified with vtune that the kernel data is roughly correct,
>just user space profiling was slightly bogus (right, Doug, or
>do I misrepresent that?)
>
>-Andi
>
>--
>ak@...ux.intel.com -- Speaking for myself only.
--
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