CLOCK_MONOTONIC datagram timestamps by the kernel
From: John
Date: Sun Feb 25 2007 - 16:48:28 EST
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.)
Regards.
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