From: Steven Rostedt <rostedt@goodmis.org>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>,
Hagen Paul Pfeifer <hagen@jauu.net>,
"Frank Ch. Eigler" <fche@elastic.org>,
Satoru Moriya <satoru.moriya@hds.com>,
David Miller <davem@davemloft.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"tgraf@infradead.org" <tgraf@infradead.org>,
"stephen.hemminger@vyatta.com" <stephen.hemminger@vyatta.com>,
"eric.dumazet@gmail.com" <eric.dumazet@gmail.com>,
Seiji Aguchi <seiji.aguchi@hds.com>,
fche@sourceware.org, mathieu.desnoyers@polymtl.ca
Subject: Re: [PATCH v2 0/2] Tracepoint for tcp retransmission
Date: Mon, 06 Feb 2012 11:18:09 -0500 [thread overview]
Message-ID: <1328545089.2200.13.camel@gandalf.stny.rr.com> (raw)
In-Reply-To: <20120206155305.GB3620@hmsreliant.think-freely.org>
On Mon, 2012-02-06 at 10:53 -0500, Neil Horman wrote:
> Yes, that was his point. Mine was that, given Satoru's needs, a netfilter hook
> provides 90% of what they need (as its been described here). If you're
> unfamiliar with them, netfilter hooks are those standard points in the network
> input/output/forwarding paths at which we can watch and maniupulate network
> traffic. They're what iptables/ip6tables/ebtables/etc use to do everything they
> do. I'm suggesting that they use those existing hooks to monitor outgoing
> traffic for whatever information they want (in this case retransmitted unacked
> tcp sequence numbers). Or whatever else their interested in.
>
> As for the other 10% (recording failed retransmits, which don't generate
> traffic), we have existing tracepoints that can be used.
I haven't looked at the details here, but I'm wondering if netfilter
could benefit from static_branch() calls (aka jump-labels). I'm sure
selinux could too. Basically, when netfilter is disabled, the fast path
would just include a nop, with no if() branch testing at all. When you
enable netfilters, it would then add a jmp to the code that actually
does the tests.
-- Steve
next prev parent reply other threads:[~2012-02-06 16:18 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-20 18:07 [PATCH v2 0/2] Tracepoint for tcp retransmission Satoru Moriya
2012-01-20 18:08 ` [PATCH v2 1/2] tcp: refactor tcp_retransmit_skb() for a single return point Satoru Moriya
2012-01-20 18:09 ` [PATCH v2 2/2] tcp: add tracepoint for tcp retransmission Satoru Moriya
2012-01-20 18:50 ` [PATCH v2 0/2] Tracepoint " David Miller
2012-02-03 21:47 ` Satoru Moriya
2012-02-04 4:40 ` Yuchung Cheng
2012-02-06 18:32 ` Satoru Moriya
2012-02-04 14:28 ` Neil Horman
2012-02-04 15:58 ` Hagen Paul Pfeifer
2012-02-04 20:09 ` Neil Horman
2012-02-05 12:53 ` Frank Ch. Eigler
2012-02-05 19:17 ` Neil Horman
2012-02-05 20:04 ` Hagen Paul Pfeifer
2012-02-05 21:48 ` David Miller
2012-02-06 1:32 ` Neil Horman
2012-02-06 15:20 ` Frank Ch. Eigler
2012-02-06 15:24 ` Eric Dumazet
2012-02-06 15:38 ` Neil Horman
2012-02-06 15:53 ` Neil Horman
2012-02-06 16:18 ` Steven Rostedt [this message]
2012-02-06 17:02 ` Eric Dumazet
2012-02-06 17:18 ` Steven Rostedt
2012-02-06 16:21 ` Frank Ch. Eigler
2012-02-06 18:21 ` Satoru Moriya
2012-01-25 13:27 ` Hagen Paul Pfeifer
2012-01-25 14:44 ` Eric Dumazet
2012-01-26 18:51 ` David Miller
2012-02-03 20:31 ` Satoru Moriya
2012-02-03 20:43 ` Satoru Moriya
2012-02-03 20:55 ` Hagen Paul Pfeifer
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