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From: Nathan Zimmer <nzimmer@sgi.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Nathan Zimmer <nzimmer@sgi.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	adobriyan@gmail.com, Alexander Viro <viro@zeniv.linux.org.uk>,
	David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH] fs/proc: Move kfree outside pde_unload_lock
Date: Fri, 24 Aug 2012 09:48:52 -0500	[thread overview]
Message-ID: <20120824144852.GA18850@gulag1.americas.sgi.com> (raw)
In-Reply-To: <1345671778.5158.2369.camel@edumazet-glaptop>

On Wed, Aug 22, 2012 at 11:42:58PM +0200, Eric Dumazet wrote:
> On Wed, 2012-08-22 at 20:28 +0200, Eric Dumazet wrote:
> 
> > 
> > Thats interesting, but if you really want this to fly, one RCU
> > conversion would be much better ;)
> > 
> > pde_users would be an atomic_t and you would avoid the spinlock
> > contention.
> 
> Here is what I had in mind, I would be interested to know how it helps a 512 core machine ;)
> 

Here are the results and they look great.

cpuinfo	baseline	moved kfree	Rcu 
tasks	read-sec	read-sec	read-sec
1	0.0141		0.0141		0.0141
2	0.0140		0.0140		0.0142
4	0.0140		0.0141		0.0141
8	0.0145		0.0145		0.0140
16	0.0553		0.0548		0.0168
32	0.1688		0.1622		0.0549
64	0.5017		0.3856		0.1690
128	1.7005		0.9710		0.5038
256	5.2513		2.6519		2.0804
512	8.0529		6.2976		3.0162




  parent reply	other threads:[~2012-08-24 14:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-22 16:38 [PATCH] fs/proc: Move kfree outside pde_unload_lock Nathan Zimmer
2012-08-22 16:38 ` [PATCH] fs/prof: Update comment on pde_unload_lock Nathan Zimmer
2012-08-22 18:28 ` [PATCH] fs/proc: Move kfree outside pde_unload_lock Eric Dumazet
2012-08-22 21:42   ` Eric Dumazet
2012-08-23 17:54     ` Nathan Zimmer
2012-08-24 14:48     ` Nathan Zimmer [this message]
2012-08-24 14:58       ` Eric Dumazet
2012-08-24 16:45         ` Nathan Zimmer
2012-08-24 21:43           ` Nathan Zimmer
2012-08-28 20:38     ` Alexey Dobriyan
2012-08-29  4:11       ` Eric Dumazet
2012-08-29  8:32         ` Alexey Dobriyan
2012-08-29 13:50         ` Alexey Dobriyan
2012-08-29 14:24           ` Eric Dumazet
2012-09-17 15:57             ` Nathan Zimmer

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