Message-ID: <49682C05.7030407@zytor.com>
Date: Fri, 09 Jan 2009 21:03:01 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Linus Torvalds <torvalds@linux-foundation.org>
CC: Harvey Harrison <harvey.harrison@gmail.com>, Ingo Molnar <mingo@elte.hu>,
       Andi Kleen <andi@firstfloor.org>, Chris Mason <chris.mason@oracle.com>,
       Peter Zijlstra <peterz@infradead.org>,
       Steven Rostedt <rostedt@goodmis.org>, paulmck@linux.vnet.ibm.com,
       Gregory Haskins <ghaskins@novell.com>, Matthew Wilcox <matthew@wil.cx>,
       Andrew Morton <akpm@linux-foundation.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       linux-fsdevel <linux-fsdevel@vger.kernel.org>,
       linux-btrfs <linux-btrfs@vger.kernel.org>,
       Thomas Gleixner <tglx@linutronix.de>, Nick Piggin <npiggin@suse.de>,
       Peter Morreale <pmorreale@novell.com>,
       Sven Dietrich <SDietrich@novell.com>,
       Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning
References: <4966AB74.2090104@zytor.com> <20090109133710.GB31845@elte.hu>  <alpine.LFD.2.00.0901090759420.6528@localhost.localdomain>  <20090109204103.GA17212@elte.hu>  <alpine.LFD.2.00.0901091251380.6528@localhost.localdomain>  <20090109213442.GA20051@elte.hu> <1231537320.5726.2.camel@brick>  <alpine.LFD.2.00.0901091347170.6528@localhost.localdomain>  <20090109231227.GA25070@elte.hu>  <alpine.LFD.2.00.0901091522250.6528@localhost.localdomain>  <20090110010125.GA31031@elte.hu> <1231549697.5700.7.camel@brick> <alpine.LFD.2.00.0901091713150.6528@localhost.localdomain>
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Linus Torvalds wrote:
> 
> There's none. In fact, it's wrong, unless you _also_ have an extern 
> definition (according to the "new" gcc rules as of back in the days).
> 
> Of course, as long as "inline" really means _always_ inline, it won't 
> matter. So in that sense Ingo is right - we _could_. Which has no bearing 
> on whether we _should_, of course.
> 

I was thinking about experimenting with this, to see what level of
upside it might add.  Ingo showed me numbers which indicate that a
fairly significant fraction of the cases where removing inline helps is
in .h files, which would require code movement to fix.  Hence to see if
it can be automated.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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