Date: Fri, 23 Dec 2005 14:57:46 +0000
From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Andrew Morton <akpm@osdl.org>
Cc: Nicolas Pitre <nico@cam.org>, hch@infradead.org, alan@lxorguk.ukuu.org.uk,
       arjan@infradead.org, mingo@elte.hu, linux-kernel@vger.kernel.org,
       torvalds@osdl.org, arjanv@infradead.org, jes@trained-monkey.org,
       zwane@arm.linux.org.uk, oleg@tv-sign.ru, dhowells@redhat.com,
       bcrl@kvack.org, rostedt@goodmis.org, ak@suse.de
Subject: Re: [patch 0/9] mutex subsystem, -V4
Message-ID: <20051223145746.GA2077@flint.arm.linux.org.uk>
Mail-Followup-To: Andrew Morton <akpm@osdl.org>,
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	alan@lxorguk.ukuu.org.uk, arjan@infradead.org, mingo@elte.hu,
	linux-kernel@vger.kernel.org, torvalds@osdl.org,
	arjanv@infradead.org, jes@trained-monkey.org,
	zwane@arm.linux.org.uk, oleg@tv-sign.ru, dhowells@redhat.com,
	bcrl@kvack.org, rostedt@goodmis.org, ak@suse.de
References: <20051222122011.GA20789@elte.hu> <20051222050701.41b308f9.akpm@osdl.org> <1135257829.2940.19.camel@laptopd505.fenrus.org> <20051222054413.c1789c43.akpm@osdl.org> <1135260709.10383.42.camel@localhost.localdomain> <20051222153014.22f07e60.akpm@osdl.org> <20051222233416.GA14182@infradead.org> <20051222221311.2f6056ec.akpm@osdl.org> <Pine.LNX.4.64.0512230912220.26663@localhost.localdomain> <20051223065118.95738acc.akpm@osdl.org>
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On Fri, Dec 23, 2005 at 06:51:18AM -0800, Andrew Morton wrote:
> Nicolas Pitre <nico@cam.org> wrote:
> > How can't you get the fact that semaphores could _never_ be as simple as 
> > mutexes?  This is a theoritical impossibility, which maybe turns out not 
> > to be so true on x86, but which is damn true on ARM where the fast path 
> > (the common case of a mutex) is significantly more efficient.
> 
> I did notice your comments.  I'll grant that mutexes will save some tens of
> fastpath cycles on one minor architecture.  Sorry, but that doesn't seem
> very important.

Wow.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core
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