Messages in this thread | | | Date | Sun, 25 Feb 2007 22:29:48 +0100 | From | John <> | Subject | CLOCK_MONOTONIC datagram timestamps by the kernel |
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Hello,
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).
SIOCGSTAMP 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 CLOCK_MONOTONIC clock.
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.)
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