From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Pádraig Brady" <P@draigBrady.com>
Cc: "Bruce \"Brutus\" Curtis" <brutus@google.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH v2] net-tcp: TCP/IP stack bypass for loopback connections
Date: Thu, 23 Aug 2012 13:40:15 +0200 [thread overview]
Message-ID: <1345722015.5904.675.camel@edumazet-glaptop> (raw)
In-Reply-To: <50360C81.6000009@draigBrady.com>
On Thu, 2012-08-23 at 11:57 +0100, Pádraig Brady wrote:
> Just to quantify the loopback testing compat issue.
> I often do stuff like the following to test latency.
> Will that be impacted?
>
> tc qdisc add dev lo root handle 1:0 netem delay 20msec
>
Yes this will. At least for tcp traffic this wont "work".
TCP friends bypass layers, by directly queuing skbs to sockets.
-> no iptables,
no qdisc (by default there is no qdisc on lo),
no loopback stats (ifconfig lo).
some SNMP stats missing as well (netstat -s)
> As for the stated tcpdump change,
> I don't suppose it would be possible to dynamically
> disable this (for new connections at least)
> while lo is being dumped?
This could be done, but it might be better to let the admin globally
enable/disable TCP friends...
next prev parent reply other threads:[~2012-08-23 11:40 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-10 0:52 [PATCH v2] net-tcp: TCP/IP stack bypass for loopback connections Bruce "Brutus" Curtis
2012-08-14 3:12 ` [PATCH] TCP/IP stack bypass for loopback connections fix Weiping Pan
2012-08-14 6:31 ` [PATCH v2] net-tcp: TCP/IP stack bypass for loopback connections Bill Fink
2012-08-14 7:37 ` David Miller
2012-08-23 16:41 ` Stephen Clark
2012-08-14 16:19 ` Bruce Curtis
2012-08-15 5:24 ` Bill Fink
2012-08-15 5:39 ` David Miller
2012-08-15 16:17 ` Bill Fink
2012-08-14 21:22 ` David Miller
2012-08-14 21:45 ` Bruce Curtis
2012-08-14 21:50 ` David Miller
2012-08-23 10:57 ` Pádraig Brady
2012-08-23 11:40 ` Eric Dumazet [this message]
2012-09-09 17:54 ` Jan Engelhardt
2012-09-09 21:39 ` David Miller
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