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From: John <>
Subject: CLOCK_MONOTONIC datagram timestamps by the kernel
Date: Sun, 25 Feb 2007 22:29:48 +0100	[thread overview]
Message-ID: <> (raw)


It is possible to ask Linux to timestamp incoming datagrams when they
are received, then to retrieve this timestamp with an ioctl command or
a recvmsg call (which would save one round trip to kernel space).

     Return a struct timeval with the receive timestamp of the last
packet passed to the user. This is useful for accurate round trip time
measurements. See setitimer(2) for a description of struct timeval.

As far as I understand, this timestamp is given by the CLOCK_REALTIME
clock. I would like to get the timestamp given by a different clock: the

In other words, I would like the kernel to do the equivalent of

   struct timespec spec;
   clock_gettime(CLOCK_MONOTONIC, &spec)

for each datagram the system receives, as soon as it is received.

Is there a way to achieve that?

Is there a different ioctl perhaps? (I don't think so.)


             reply	other threads:[~2007-02-25 21:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-25 21:29 John [this message]
2007-02-26 10:26 ` John
2007-02-26 12:20   ` Andi Kleen
2007-02-26 14:17     ` John
2007-02-28 11:23       ` John

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