What is NLV?

NLV is the NetLogger Visualization tool. NLV allows you to graph NetLogger output and examine important features of the data. Its main graphical element is a linked series of discrete events called a lifeline, but it can also display time/value graphs. Data from multiple sources can be correlated by time and by common elements (visually, by color).

Getting NLV

The quickest way to get NLV is to follow the 'Download' link at left and unzip one of the archives. NLV is available as a binary distribution only, for Linux only. Email Dan Gunter for information about getting versions for other architectures.

Using NLV

The best way to diagnose various types of network problems is to run a real distributed application to collect timing information for all important events. First, you instrument your code with the NetLogger toolkit , then you look at the static or dynamic (real-time) output with NLV. For more information on how, exactly, this is done, please refer to the Running page(s). Once NLV is displaying your output, you can look for patterns of errors or delays at various scales. In the near future, NLV will include the capability to perform user-defined calculations over the data, which can be displayed as the data scrolls by in real-time. In general NLV is one piece of an overall system for finding and analyzing network bottlenecks. It provides a view of the data, and compresses it into a form that can be fed to a tool which can automatically detect problem-spots and generate alarms which autonomous agents can receive and act upon.