From: Dimitris Michailidis <dm@chelsio•com>
To: David Miller <davem@davemloft•net>
Cc: therbert@google•com, eric.dumazet@gmail•com, netdev@vger•kernel.org
Subject: Re: [PATCH net-next-2.6] net: Consistent skb timestamping
Date: Sun, 16 May 2010 11:30:50 -0700 [thread overview]
Message-ID: <4BF039DA.3020207@chelsio.com> (raw)
In-Reply-To: <20100515.235635.63009445.davem@davemloft.net>
David Miller wrote:
> The real fix is to make the devices less stupid and give us timestamps
> directly, and thanks to things like PTP support in hardware that's
> actually more and more of a reality these days.
For cxgb4 a timestamp is written into Rx descriptors for each received
packet. The value comes from a TSC-like cycle counter. The raw timestamp
is very cheap to get, its value converted to system ktime a bit less so
though not too bad. It would be nicer though if the stack could hint the
driver whether it should do the conversion at all. Maybe export
netstamp_needed and add an inline wrapper to read it?
prev parent reply other threads:[~2010-05-16 18:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-06 12:01 [PATCH net-next-2.6] net: Consistent skb timestamping Eric Dumazet
2010-05-06 15:12 ` Tom Herbert
2010-05-06 15:37 ` Eric Dumazet
2010-05-06 16:14 ` Eric Dumazet
2010-05-16 6:57 ` David Miller
2010-05-16 6:56 ` David Miller
2010-05-16 18:30 ` Dimitris Michailidis [this message]
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