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From: Roland Dreier <rdreier@cisco.com>
To: Darren Hart <dvhltc@us.ibm.com>
Cc: "lkml\, " <linux-kernel@vger.kernel.org>,
       Steven Rostedt <rostedt@goodmis.org>,
       Peter Zijlstra <peterz@infradead.org>,
       Gregory Haskins <ghaskins@novell.com>,
       Sven-Thorsten Dietrich <sdietrich@novell.com>,
       Peter Morreale <pmorreale@novell.com>,
       Chris Wright <chrisw@sous-sol.org>,
       Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
       Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: RFC: Ideal Adaptive Spinning Conditions
References: <4BB3D90C.3030108@us.ibm.com>
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Date: Wed, 31 Mar 2010 16:35:53 -0700
In-Reply-To: <4BB3D90C.3030108@us.ibm.com> (Darren Hart's message of "Wed, 31
	Mar 2010 16:21:48 -0700")
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 > I'm looking at some adaptive spinning with futexes as a way to help
 > reduce the dependence on sched_yield() to implement userspace
 > spinlocks. Chris, I included you in the CC after reading your comments
 > regarding sched_yield() at kernel summit and I thought you might be
 > interested.

I think you may have the wrong Chris.  Chris Wright wasn't at the most
recent kernel summit and I do have a vague recollection of Chris Mason
mentioning that Oracle developers found that sched_yield() performed
better than futexes + kernel scheduling.
-- 
Roland Dreier <rolandd@cisco.com> || For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/index.html