Opened 10 years ago

Closed 10 years ago

Last modified 7 years ago

#1335 closed defect (fixed)

Low value for Xm gives high build timeout

Reported by: mikeperry Owned by: mikeperry
Priority: Low Milestone: Tor: 0.2.2.x-final
Component: Core Tor/Tor Version:
Severity: Keywords:
Cc: mikeperry, arma, Sebastian, ilter Actual Points:
Parent ID: Points:
Reviewer: Sponsor:

Description (last modified by mikeperry)

My tor client just learned a timeout of 42, despite having the majority of my timeouts below 2s. I suspect
this is because the Xm value was 275, but I still had quite a bit of timeouts after that. This caused the tor client
to calculate a really small alpha, resulting in a shallow curve.

I am not sure what to do about this. I suspect what I'm actually looking at is 2 or 3 curves: one for each guard.
We could try learning timeouts independently per guard (fragile, bulky), or we could try a different way to calculate
Xm - maybe mean or median of 3 highest modes?

It could also be that the synthetic timeouts I created were very high, and are also causing alpha to be low. I'm
attaching the state file to experiment with in the future.

[Automatically added by flyspray2trac: Operating System: All]

Child Tickets

Attachments (3)

state (0 bytes) - added by mikeperry 10 years ago.
mikeperry-state (0 bytes) - added by mikeperry 10 years ago.
torperf-state (58.8 KB) - added by mikeperry 10 years ago.

Download all attachments as: .zip

Change History (9)

Changed 10 years ago by mikeperry

Attachment: state added

comment:1 Changed 10 years ago by mikeperry

Weighted mean of 3-5 highest modes might not be a bad idea.

comment:2 Changed 10 years ago by mikeperry

Part of this bug should also include updating path-spec.txt to document all of the CBT stuff, including this change.

comment:3 Changed 10 years ago by mikeperry

We have a couple other datapoints for this bug. Possibly related to Bug 1248, we may need to cap our synthetic
timeouts to be something much lower.. Am going to attach a state file for moria, which seems to exhibit this
issue, and a new state file for me, which may be suffering from both problems.

Changed 10 years ago by mikeperry

Attachment: mikeperry-state added

Changed 10 years ago by mikeperry

Attachment: torperf-state added

comment:4 Changed 10 years ago by nickm

Milestone: Tor: 0.2.2.x-final
Version: 1.2.4

comment:5 Changed 10 years ago by mikeperry

Description: modified (diff)
Resolution: Nonefixed
Status: newclosed

Fix should appear in 0.2.2.14.

comment:6 Changed 7 years ago by nickm

Component: Tor ClientTor
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