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* CLOCK_MONOTONIC datagram timestamps by the kernel
@ 2007-02-25 21:29 John
  2007-02-26 10:26 ` John
  0 siblings, 1 reply; 5+ messages in thread
From: John @ 2007-02-25 21:29 UTC (permalink / raw)
  To: linux-kernel; +Cc: johnstul, mingo, zippel, tglx, linux.kernel, akpm


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.)


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2007-02-28 11:23 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2007-02-25 21:29 CLOCK_MONOTONIC datagram timestamps by the kernel John
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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