Implement PID control feedback for bw auths

We should be able to get better feedback measurements from bw authorites if we make them smarter about tracking when they last measured a relay. They should only apply their ALPHA feedback loop if they have a new measurement in this round of voting.

This should fix the feedback problems we saw when we turned this feature on before.

changed milestone to %Deliverable-Nov2011

added MikePerryIteration20111106 actualpoints::26 component::core tor/torflow milestone::Deliverable-Nov2011 owner::mikeperry parent::2769 points::10 priority::high resolution::fixed status::closed type::enhancement labels

We need to double check the timestamp field to ensure that it is really the measurement time, but otherwise this should be as simple as comparing the measurement timestamp to the timestamp from the current consensus.

We may want to SETCONF both FetchDirInfoExtraEarly and FetchDirInfoEarly to ensure we get a consensus every hour, so that we know if the measurement was after it was published, and we know the most recent value.

Adding this to the list of experiments for the tech report, though we may not get to it till right before the camera deadline.

Trac:
Actualpoints: N/A to N/A
Points: N/A to N/A
Parent: N/A to #2769 (closed)

#2550 (moved) is potentially going to change how this works, because of the delay in choosing an advertised value..

Trac:
Type: defect to enhancement

Trac:
Milestone: N/A to Deliverable-Nov2011
Priority: normal to major
Status: new to needs_information

What is with the radiobutton juggling...

Trac:
Status: needs_information to accepted

Trac:
Points: N/A to 10
Keywords: N/A deleted, MikePerryIterationReport2011106 added

Trac:
Keywords: MikePerryIterationReport2011106 deleted, MikePerryIteration20111106 added

This is now running on the chicago vm (which votes to urrass). See https://gitweb.torproject.org/mikeperry/torflow.git/blob/pid_control:/NetworkScanners/BwAuthority/README.spec.txt section 3 for details.

I included a fix for #1984 (moved), as well.

We'll see how it goes.

Trac:
Cc: N/A to karsten

Spent quite a bit of time on this. It appears to be running fine on one bw auth. I created #4425 (moved) to monitor it and deploy on the others.

Trac:
Summary: Bw Authorities should apply ALPHA multiplier only if measurements change to Implement PID control feedback for bw auths
Status: accepted to closed
Actualpoints: N/A to 26
Resolution: N/A to fixed

closed

changed time estimate to 80h

added 208h of time spent

mentioned in issue #1984 (moved)

mentioned in issue #2550 (moved)

mentioned in issue #4425 (moved)

mentioned in issue #5464 (moved)

mentioned in issue #13865 (moved)

moved to tpo/network-health/torflow#1976 (closed)

mentioned in issue tpo/network-health/torflow#4425 (closed)