On 6/10/07, Gerrit Renker <gerrit@xxxxxxxxxxxxxx> wrote:
[CCID3]: Ignore trivial amounts of elapsed time
This patch fixes a previously undiscovered bug:
* the receive timestamp is taken when the skb enters the CCID3 module;
* RFC 4342 requires to send an Elapsed Time estimate to the sender;
* the bug is in computing the elapsed time as the time between `receiving'
the packet (i.e. skb enters CCID module) and sending feedback,
--> there is no layer-processing, queueing, or delay involved,
--> hence the elapsed time is in the order of 1 function call
--> this is in the dimension of maximally 50..100usec
--> which renders the use of elapsed time almost entirely useless.
The fix is simply to ignore such trivial amounts of elapsed time.
What is the bug? Do you mean it is useless to do this? Or is there
another problem?
Reading RFC4340, 13.2 and thinking about pre-emptible kernels causes
me to ask this question - what happens if you lose the time slice you
are on in between the calls - then it would be much higher time
difference....
--
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WAND Network Research Group
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