From: Eric Dumazet <eric.dumazet@gmail.com>
To: Richard Cochran <richardcochran@gmail.com>
Cc: Ingo Kofler <ikofler@edu.uni-klu.ac.at>, netdev@vger.kernel.org
Subject: Re: Problems obtaining software TX timestamps
Date: Thu, 09 Sep 2010 20:58:50 +0200 [thread overview]
Message-ID: <1284058730.2298.74.camel@edumazet-laptop> (raw)
In-Reply-To: <20100909173228.GA2657@riccoc20.at.omicron.at>
Le jeudi 09 septembre 2010 à 19:32 +0200, Richard Cochran a écrit :
> On Thu, Sep 09, 2010 at 04:02:38PM +0200, Eric Dumazet wrote:
> > Should drivers call it at start_xmit() time, or at tx completion time ?
>
> IMHO, it should be done as immediately after the buffer has been
> handed off to the hardware. Not all MACs have a completion method, so
> that would at least make the "rule" consistent.
>
Well, all drivers must release skb *somewhere*, either in their
ndo_start_xmit() or TX completion ;)
> In general, the goals of high volume and timestamp accuracy are in
> conflict (unless you have HW timestamping). If users are relying on SW
> timestamping, then they should be aware of the fact that high network
> traffic will spoil their fun.
>
- Full duplex mode wanted
- And small TX rings
prev parent reply other threads:[~2010-09-09 18:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-08 12:11 Problems obtaining software TX timestamps Ingo Kofler
2010-09-08 15:12 ` Eric Dumazet
2010-09-08 21:21 ` Ingo Kofler
2010-09-08 21:24 ` David Miller
2010-09-09 6:35 ` Richard Cochran
2010-09-09 8:26 ` Ingo Kofler
2010-09-09 13:57 ` Richard Cochran
2010-09-09 14:02 ` Eric Dumazet
2010-09-09 14:31 ` Loke, Chetan
2010-09-09 17:32 ` Richard Cochran
2010-09-09 18:58 ` Eric Dumazet [this message]
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