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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Hans Schillstrom <hans.schillstrom@ericsson.com>
Cc: "paulmck@linux.vnet.ibm.com" <paulmck@linux.vnet.ibm.com>,
	Daniel Lezcano <daniel.lezcano@free.fr>,
	"lvs-devel@vger.kernel.org" <lvs-devel@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"netfilter-devel@vger.kernel.org"
	<netfilter-devel@vger.kernel.org>,
	"horms@verge.net.au" <horms@verge.net.au>,
	"ja@ssi.bg" <ja@ssi.bg>,
	"wensong@linux-vs.org" <wensong@linux-vs.org>
Subject: Re: [RFC PATCH 1/9] ipvs network name space aware
Date: Thu, 21 Oct 2010 10:01:12 +0200	[thread overview]
Message-ID: <1287648072.6871.15.camel@edumazet-laptop> (raw)
In-Reply-To: <201010210945.55252.hans.schillstrom@ericsson.com>

Le jeudi 21 octobre 2010 à 09:45 +0200, Hans Schillstrom a écrit :
> I do have this (and some debuging)
> __rcu_read_lock()
> => 0xffffffff8108bcf3 <+0>:	push   %rbp
>    0xffffffff8108bcf4 <+1>:	mov    %rsp,%rbp
>    0xffffffff8108bcf7 <+4>:	nopl   0x0(%rax,%rax,1)
>    0xffffffff8108bcfc <+9>:	mov    %gs:0xb540,%rax
>    0xffffffff8108bd05 <+18>:	mov    0x108(%rax),%edx
>    0xffffffff8108bd0b <+24>:	inc    %edx
>    0xffffffff8108bd0d <+26>:	mov    %edx,0x108(%rax)
>    0xffffffff8108bd13 <+32>:	leaveq
>    0xffffffff8108bd14 <+33>:	retq
> 
> which is not that many, actually imprerssing few instructions :-)

nopl   0x0(%rax,%rax,1) is a filler because of extra instrumentation in
your kernel.

Maybe you could find out why your compiler dont use

	incl 0x108(%rax)

instead of

	mov    0x108(%rax),%edx
	inc    %edx
	mov    %edx,0x108(%rax)


So rcu_read_lock() is really _two_ instructions.

I agree with Paul with the "few" qualification... :-)



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  reply	other threads:[~2010-10-21  8:01 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-08 11:16 [RFC PATCH 1/9] ipvs network name space aware Hans Schillstrom
2010-10-18  8:59 ` Daniel Lezcano
2010-10-18  9:54   ` Hans Schillstrom
2010-10-18 11:37     ` Daniel Lezcano
2010-10-18 13:23       ` Hans Schillstrom
2010-10-18 14:26         ` Daniel Lezcano
2010-10-19 18:44         ` Paul E. McKenney
2010-10-20  8:25           ` Hans Schillstrom
2010-10-20 16:02             ` Paul E. McKenney
2010-10-21  7:45               ` Hans Schillstrom
2010-10-21  8:01                 ` Eric Dumazet [this message]
2010-10-21 15:18                   ` Paul E. McKenney
2010-10-21  8:58               ` Eric Dumazet
2010-10-21 15:16                 ` Paul E. McKenney
2010-10-21 15:24                   ` Eric Dumazet

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