Modify test network schedule start times for exponential backoff

changed milestone to %Tor: unspecified

added actualpoints::0.5 component::core tor/tor doc milestone::Tor: unspecified points::0.5 priority::medium resolution::fixed severity::normal status::closed triaged-out-20170116 type::enhancement labels

There is no initial delay at which bootstrap works in the test network at exponent 4 (multiplier 3). This is because it takes 5-10 seconds for the initial consensus to be created. Ideally, we want relays and clients to wait 10 seconds before trying their first download. Then we want them to download with linear or low multiplier exponential delays starting at 0 or 1. But the exponential backoff code does not have this option.

If we start with a low delay and high multiplier, by the time that consensus is created, the variance among the backoff times is so high that some clients and relays work, and others do not.

We also can't change these schedules in Tor, because chutney explicitly sets them all to "0, 5". (And the exponential backoff code only uses the initial "0".)

The solution is to reduce the exponent to 3 (multiplier 2), but only in test networks. (The original exponential backoff code had exponent 2 (multiplier 1), and with delay increments in [0, delaymultiplier]. But I chose exponent 3 (multiplier 2) to get as close to the live network code as possible. It seems just as reliable. It's also worth noting that the delay increments are now in [1, delaymultiplier].)

Perhaps we can make this a configurable option, but that can wait for a later release. Perhaps we could also stop setting these options in chutney as well. But this works well enough for now.

Please see my branch bug20597_029 on github.

Trac:
Status: new to needs_review
Actualpoints: N/A to 0.5

Trac:
Keywords: N/A deleted, CoreTorTeam201611 added

wow, that is messy. this patch looks like an acceptable stopgap, though. So, merging it.

Let's open tickets for an improved solution?

#20604 (moved), #20605 (moved), #20606 (moved), #20607 (moved), all parented to #20534 (moved) so we remember to document this.

Trac:
Milestone: Tor: 0.2.9.x-final to Tor: 0.3.0.x-final
Keywords: CoreTorTeam201611, must-fix-before-0295-alpha, regression, 029-proposed deleted, CoreTorTeam201611 doc added
Status: needs_review to new

batch modify: I think these are "enhancement", though I could be wrong about some.

Trac:
Type: defect to enhancement

Trac:
Milestone: Tor: 0.3.0.x-final to Tor: unspecified
Keywords: CoreTorTeam201611 doc deleted, triaged-out-20160116, CoreTorTeam201611, doc added