From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jarek Poplawski <jarkao2@gmail.com>
Subject: Re: [PATCH net-next-2.6] net: force a fresh timestamp for ingress
 packets
Date: Thu, 16 Dec 2010 23:42:37 +0100
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Cc: David Miller <davem@davemloft.net>,
	Changli Gao <xiaosuo@gmail.com>,
	netdev <netdev@vger.kernel.org>,
	Patrick McHardy <kaber@trash.net>
To: Eric Dumazet <eric.dumazet@gmail.com>
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On Thu, Dec 16, 2010 at 11:26:03PM +0100, Eric Dumazet wrote:
> Le jeudi 16 d=E9cembre 2010 ?? 23:08 +0100, Jarek Poplawski a =E9crit=
 :
>=20
> > Hmm... Do you expect more people start debugging SFQ or I missed yo=
ur
> > point? ;-) Maybe such a change would be reasonable on a cloned skb?
>=20
> My point was to permit an admin to check his ingress shaping works or
> not. In this respect, netem was a specialization of a general problem=
=2E
>=20
> We had a prior discussion on timestamping skb in RX path, when RPS ca=
me
> in : Should we take timestamp before RPS or after. At that time we ad=
ded
> a sysctl. Not sure it was the right choice :-(
>=20
> I feel tcpdump (on TX side) should really display time of packet righ=
t
> before being given to device, but this is probably a matter of taste.

It might be reasonable unless it changes data for later users. That's
why I mentioned cloning.

>=20
> Before commit 8caf153974f2 (net: sch_netem: Fix an inconsistency in
> ingress netem timestamps.), this is what was done.

Then why don't you try to let turn it off in netem, where it only
matters?

Jarek P.