[tor-commits] [tor/master] Bug 40168 changes file

[asn at torproject.org]

commit 1fadb1bdf12610970af0ae9c7affd300830c3509
Author: Mike Perry <mikeperry-git at torproject.org>
Date:   Tue Nov 3 14:39:10 2020 -0600

    Bug 40168 changes file
---
 changes/bug40168 | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/changes/bug40168 b/changes/bug40168
new file mode 100644
index 0000000000..c52a0352c2
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+  o Minor bugfixes (circuit build timeout):
+    - Improve the accuracy of our circuit build timeout calculation for 60%,
+      70%, and 80% build rates for various guard choices. We now use a maximum
+      likelihood estimator for Pareto parameters of the circuit build time
+      distribution, instead of a "right-censored estimator". This causes
+      clients to ignore circuits that never finish building in their timeout
+      calculations. Previously, clients were counting such unfinished circuits
+      as having the highest possible build time value, when in reality these
+      circuits most likely just contain relays that are offline. We also now
+      wait a bit longer to let circuits complete for measurement purposes,
+      lower the minimum possible effective timeout from 1.5 seconds to 10ms,
+      and increase the resolution of the circuit build time histogram from
+      50ms bin widths to 10ms bin widths. Additionally, we alter our estimate
+      Xm by taking the maximum of the top 10 most common build time values
+      of the 10ms histogram, and compute Xm as the average of these.
+      Fixes bug 40168; bugfix on 0.2.2.14-alpha.