netdev - [PATCH net-net] net: loopback: set default mtu to 64K

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <1348475339.26828.188.camel@edumazet-glaptop>
Date:	Mon, 24 Sep 2012 10:28:59 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev <netdev@...r.kernel.org>
Subject: [PATCH net-net] net: loopback: set default mtu to 64K

From: Eric Dumazet <edumazet@...gle.com>

loopback current mtu of 16436 bytes allows no more than 3 MSS TCP
segments per frame, or 48 Kbytes. Changing mtu to 64K allows TCP
stack to build large frames and significantly reduces stack overhead.

Performance boost on bulk TCP transferts can be up to 30 %, partly
because we now have one ACK message for two 64KB segments, and a lower
probability of hitting /proc/sys/net/ipv4/tcp_reordering default limit.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 drivers/net/loopback.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 4a075ba..81f8f9e 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -157,7 +157,7 @@ static const struct net_device_ops loopback_ops = {
  */
 static void loopback_setup(struct net_device *dev)
 {
-	dev->mtu		= (16 * 1024) + 20 + 20 + 12;
+	dev->mtu		= 64 * 1024;
 	dev->hard_header_len	= ETH_HLEN;	/* 14	*/
 	dev->addr_len		= ETH_ALEN;	/* 6	*/
 	dev->tx_queue_len	= 0;


--
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