On Fri, May 25, 2012 at 4:58 PM, Chris Friesen
[off-list ref] wrote:

On 05/22/2012 11:21 AM, Srećko Jurić-Kavelj wrote:

quoted

By looking at the code it's clear that the time stamping is done with
jiffies, and my kernel has CONFIG_HZ=100.

I understand that this is for performance reasons (and the RTT
smoothing filter is implemented with bit shifting operations), but
would using a more precise time stamp have significant impact on
performance? Since RTT is used to compute RTO, wouldn't there be any
benefits of having more accurate estimate of this value?

I don't know if it would make any difference to the tcp algorithms, but
certainly on some architectures you can get a fast and accurate hardware
timestamp.

I would be interested in someone doing that experiment in light of the
codel work.

Chris

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