From: "Pádraig Brady" <P@draigBrady•com>
To: "Bruce \"Brutus\" Curtis" <brutus@google•com>
Cc: "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 11:57:05 +0100 [thread overview]
Message-ID: <50360C81.6000009@draigBrady.com> (raw)
In-Reply-To: <1344559958-29162-1-git-send-email-brutus@google.com>
On 08/10/2012 01:52 AM, Bruce "Brutus" Curtis wrote:
> From: "Bruce \"Brutus\" Curtis" <brutus@google•com>
>
> TCP/IP loopback socket pair stack bypass, based on an idea by, and
> rough upstream patch from, David Miller <davem@davemloft•net> called
> "friends", the data structure modifcations and connection scheme are
> reused with extensive data-path changes.
>
> A new sysctl, net.ipv4.tcp_friends, is added:
> 0: disable friends and use the stock data path.
> 1: enable friends and bypass the stack data path, the default.
>
> Note, when friends is enabled any loopback interpose, e.g. tcpdump,
> will only see the TCP/IP packets during connection establishment and
> finish, all data bypasses the stack and instead is delivered to the
> destination socket directly.
>
> Testing done on a 4 socket 2.2GHz "Quad-Core AMD Opteron(tm) Processor
> 8354 CPU" based system, netperf results for a single connection show
> increased TCP_STREAM throughput, increased TCP_RR and TCP_CRR transaction
> rate for most message sizes vs baseline and comparable to AF_UNIX.
>
> Significant increase (up to 4.88x) in aggregate throughput for multiple
> netperf runs (STREAM 32KB I/O x N) is seen.
Nice!
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
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?
cheers,
Pádraig.
next prev parent reply other threads:[~2012-08-23 10:57 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 [this message]
2012-08-23 11:40 ` Eric Dumazet
2012-09-09 17:54 ` Jan Engelhardt
2012-09-09 21:39 ` David Miller
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