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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: Eric Dumazet <dada1@cosmosbay.com>, netfilter-devel@vger.kernel.org
Subject: Re: netfilter conntrack tcp lock
Date: Tue, 21 Apr 2009 21:20:00 -0700	[thread overview]
Message-ID: <20090422042000.GC6948@linux.vnet.ibm.com> (raw)
In-Reply-To: <20090421210412.268fc4e7@nehalam>

On Tue, Apr 21, 2009 at 09:04:12PM -0700, Stephen Hemminger wrote:
> Not sure what the performance impact would be but simply changing tcp_lock
> (in nf_conntrack_proto_tcp) to a spin_lock might get a performance boost.
> I thought I heard Paul say read_locks are way slower than spin_lock.

In -rt, read_locks are really exclusive locks.  :-/

And an uncontended read_lock is somewhat slower than a spin_lock,
but not overwhelmingly so.

> Alternatively, going to some form of bit based hash lock might work.

I have to ask the stupid question...  Can conntrack entries be hashed
or otherwise partitioned, with a lock then assigned to each partition?

						Thanx, Paul

       reply	other threads:[~2009-04-22  4:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20090421210412.268fc4e7@nehalam>
2009-04-22  4:20 ` Paul E. McKenney [this message]
2009-04-22  4:57 ` netfilter conntrack tcp lock Eric Dumazet
2009-04-22 16:04   ` Patrick McHardy

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