From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: SO_REUSEPORT - can it be done in kernel?
Date: Mon, 28 Feb 2011 14:32:51 +0100
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Cc: David Miller <davem@davemloft.net>, rick.jones2@hp.com,
	therbert@google.com, wsommerfeld@google.com,
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To: Herbert Xu <herbert@gondor.apana.org.au>
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Le lundi 28 f=C3=A9vrier 2011 =C3=A0 19:36 +0800, Herbert Xu a =C3=A9cr=
it :
> On Sun, Feb 27, 2011 at 07:06:14PM +0800, Herbert Xu wrote:
> > I'm working on this right now.
>=20
> OK I think I was definitely on the right track.  With the send
> patch made lockless I now get numbers which are even better than
> those obtained with running named with multiple sockets.  That's
> right, a single socket is now faster than what multiple sockets
> were without the patch (of course, multiple sockets may still
> faster with the patch vs. a single socket for obvious reasons,
> but I couldn't measure any significant difference).
>=20
> Also worthy of note is that prior to the patch all CPUs showed
> idleness (lazy bastards!), with the patch they're all maxed out.
>=20
> In retrospect, the idleness was simply the result of the socket
> lock scheduling away and was an indication of lock contention.
>=20

Now, input path can run without finding socket locked by xmit path, so
skb are queued into receive queue, not backlog one.

> Here are the patches I used.  Please don't them yet as I intend
> to clean them up quite a bit.
>=20
> But please do test them heavily, especially if you have an AMD
> NUMA machine as that's where scalability problems really show
> up.  Intel tends to be a lot more forgiving.  My last AMD machine
> blew up years ago :)

I am going to test them, thanks !