BLT

Bandwidth and Latency Testing (BLT) Protocol

Latency, packet loss, and low bandwidth related bugs are a major problem in Second Life. One huge barrier to fixing these bugs is a lack of testing protocol to reproduce these bugs that will rarely show up for someone who lives in San Francisco, or even in America. The BLT Protocol aims to create a standardized set of test conditions that can be referred to in reproductions, and tested against during QA.

This meta-bug contains all bugs that might be related to latency, bandwidth, or packet loss: MISC-506

Reproducing a bug

If you confirm a bug under one of the test scenarios listed below, the following format should be used in the reproduction in a Jira comment:

BLT# Percentage reproduction ##%

Followed by the step-by-step reproduction of the bug, under the BLT conditions listed.

Rules

• If the reproduction percentage is less than 100%, you should try other BLT scenarios. If none are 100%, list all scenarios that reproduced the bug with the percentage for each.

• When testing a patch for the bug, every scenario listed on the bug as a reproduction scenario must be tested, and all should be 0% reproduction.

• A partial fix should be noted as such in the Jira comments, along with which scenarios still fail.

• If you can create a new scenario to reproduce the bug 100%, add that scenario to this page and assign it a BLT number.

• High percentage reproductions of a bug justify placing that bug on the upcoming triage schedule, if it is not already imported into private Jira.

Test Setup

Testing is done with the linux kernel traffic shaping and WAN emulation modules.

http://linux-net.osdl.org/index.php/Netem

Note that you will be missing the "tc" module on Ubuntu boxes, unless you get the Gutsy beta release. They just screwed up and forgot to compile it for several versions, it's a standard kernel module that should be compiled on most distros.

BLT Scenarios

In Progress...