From: Harvey Harrison <harvey.harrison@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: bunk@kernel.org, linux-kernel@vger.kernel.org,
linux-arch <linux-arch@vger.kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: Re: RFC: remove __read_mostly
Date: Thu, 13 Dec 2007 14:44:15 -0800 [thread overview]
Message-ID: <1197585855.898.33.camel@brick> (raw)
In-Reply-To: <20071213.143246.175833292.davem@davemloft.net>
On Thu, 2007-12-13 at 14:32 -0800, David Miller wrote:
> From: Adrian Bunk <bunk@kernel.org>
> Date: Thu, 13 Dec 2007 23:20:44 +0100
>
> > My question is:
> > Is there anywhere in the kernel a case where __read_mostly brings a
> > measurable improvement or can it be removed?
>
> Yes, on SMP when read-mostly objects share cache lines
> with other objects which are frequently written to.
>
> That is the whole reason we created __read_mostly
I'm curious if anyone has been looking into replacing the __read_mostly
approach with Mathieu's immediate values patchset. Wouldn't they solve
the cacheline sharing as well (perhaps more eficiently even with trading
some icache for dcache)?
Harvey
next prev parent reply other threads:[~2007-12-13 22:44 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-13 22:20 RFC: remove __read_mostly Adrian Bunk
2007-12-13 22:29 ` Andi Kleen
2007-12-13 22:41 ` Adrian Bunk
2007-12-14 16:16 ` Arnd Bergmann
2007-12-14 16:31 ` Eric Dumazet
2007-12-13 22:32 ` David Miller
2007-12-13 22:44 ` Harvey Harrison [this message]
2007-12-13 23:06 ` Andi Kleen
2007-12-13 22:48 ` Eric Dumazet
2007-12-13 23:00 ` Adrian Bunk
2007-12-13 23:54 ` Kyle McMartin
2007-12-14 0:33 ` Andi Kleen
2007-12-17 10:33 ` Andrew Morton
2007-12-17 10:53 ` Eric Dumazet
2007-12-17 11:07 ` Andrew Morton
2007-12-17 12:19 ` Andi Kleen
2007-12-17 12:15 ` Andi Kleen
2007-12-17 12:40 ` Adrian Bunk
2007-12-14 15:24 ` Matt Mackall
2007-12-14 15:38 ` Eric Dumazet
2007-12-14 15:42 ` Matt Mackall
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