microtime latency

[Joshua Lamorie <jpl@xiphos.ca>]

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Gidday there,

	I'm trying to measure round trip time of packets within the
kernel, using 'microtime'.  What is the latency on the value that comes
back from this?  I log the time when the packet leaves, and then read the
clock again when it comes back.  I get a deviation of +/- 40ms on the
round trip time (i'm using a traffic shaper to control the link).

	The logging facility is a little odd to me (I didn't write it),
but there aren't many moving parts.  I want to know if the microtime
function is guaranteed to be accurate.

	Why would ping, using 'gettimeofday' be more accurate than my own
stuff?

	Any hints would be appreciated.

Joshua

- -- 
Joshua Lamorie                           ph. 514-848-9640
Designer, Space Systems                  fx. 514-848-9644
Xiphos Technologies Inc.                 web http://www.xiphos.ca/
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