netdev - Re: [PATCH 4/5] udp: Add lockless transmit path

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 01 Mar 2011 06:30:41 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	David Miller <davem@...emloft.net>, rick.jones2@...com,
	therbert@...gle.com, wsommerfeld@...gle.com,
	daniel.baluta@...il.com, netdev@...r.kernel.org,
	Thomas Graf <tgraf@...radead.org>
Subject: Re: [PATCH 4/5] udp: Add lockless transmit path

Le lundi 28 février 2011 à 19:41 +0800, Herbert Xu a écrit :
> udp: Add lockless transmit path
> 
> The UDP transmit path has been running under the socket lock
> for a long time because of the corking feature.  This means that
> transmitting to the same socket in multiple threads does not
> scale at all.
> 
> However, as most users don't actually use corking, the locking
> can be removed in the common case.
> 
> This patch creates a lockless fast path where corking is not used.
> 
> Please note that this does create a slight inaccuracy in the
> enforcement of socket send buffer limits.  In particular, we
> may exceed the socket limit by up to (number of CPUs) * (packet
> size) because of the way the limit is computed.
> 
> As the primary purpose of socket buffers is to indicate congestion,
> this should not be a great problem for now.
> 
> Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
> ---

So far I found no obvious problem, and got pretty impressive results.

Acked-by: Eric Dumazet <eric.dumazet@...il.com>



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html