CircuitBuildTimeout Management and the Pareto Distribution

Mike Perry mikeperry at
Mon Jul 26 20:04:06 UTC 2010

Thus spake Cav (cav at

> Hi Mike,
> Thanks for a quick reply. Maybe its my warped mind that had me consider 
> that the management of timeouts (sliding the timeout up and down - as it 
> appears in the logs) would affect the distribution of timeouts and 
> therefore the pareto distribution around them.
> I will admit to experimenting with smaller values of 
> CBT_DEFAULT_QUANTILE_CUTOFF. These lead to 'peaks' in the timeout 
> distribution. The smaller the value, the tighter these 'peaks' seem to be.

This should not be the case in and above. Changing the
QUANTILE_CUTOFF default should now only govern which circuits you
actually use. Circuits should continue to build until
CBT_DEFAULT_CLOSE_QUANTILE, so the distribution of recorded buildtimes
will be much more insenitive to changes in the timeout value.

Mike Perry
Mad Computer Scientist evil labs
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