From: David Miller <davem@davemloft.net>
To: andi@firstfloor.org
Cc: juhlenko@akamai.com, netdev@vger.kernel.org,
shemminger@linux-foundation.org
Subject: Re: [RFC 0/4] net: enable timestamps on a per-socket basis
Date: Mon, 21 Apr 2008 04:51:22 -0700 (PDT) [thread overview]
Message-ID: <20080421.045122.239401136.davem@davemloft.net> (raw)
In-Reply-To: <480C7DE3.5020301@firstfloor.org>
From: Andi Kleen <andi@firstfloor.org>
Date: Mon, 21 Apr 2008 13:43:31 +0200
> Are you sure they don't just need end2end timestamps as in from sendmsg
> to recvmsg()? Imagine the packet is stuck for some time in the
> kernel for whatever reason and you only process it later in user space
> wouldn't you consider that older time stamp "inaccurate" too? I would,
> unless I was debugging the network stack.
They need the exact timestamp when the packet was received at the
physical machine (and this pretty much means the network card) so that
they know precisely when customer X's trade order arrived for
scheduling and prioritizing purposes.
> It is hard to imagine they really care about excluding one set of queues
> (kernel queue) and not other queues (nic rx/tx queues, switch queues
> etc.) for their time stamps as you imply.
They do.
prev parent reply other threads:[~2008-04-21 11:51 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-21 5:34 [RFC 0/4] net: enable timestamps on a per-socket basis Jason Uhlenkott
2008-04-21 5:34 ` [RFC 1/4] net core: move timestamp functions Jason Uhlenkott
2008-04-21 5:35 ` [RFC 2/4] net core: let protocols implement SOCK_TIMESTAMP efficiently Jason Uhlenkott
2008-04-21 5:35 ` [RFC 3/4] ipv4: efficient SOCK_TIMESTAMP support for TCP, UDP, and raw sockets Jason Uhlenkott
2008-04-21 5:36 ` [RFC 4/4] af_packet: efficient SOCK_TIMESTAMP support Jason Uhlenkott
2008-04-21 6:03 ` [RFC 0/4] net: enable timestamps on a per-socket basis David Miller
2008-04-21 7:28 ` Jason Uhlenkott
2008-04-21 10:44 ` Andi Kleen
2008-04-21 10:59 ` David Miller
2008-04-21 11:43 ` Andi Kleen
2008-04-21 11:51 ` David Miller [this message]
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