In this paper we study a 3D tubular visualization of software activity log data, with the aim of supporting multithreaded software development and debugging. We consider an existing visualization called Datatube2 that has already been used to help various domain experts in the analysis of large amounts of time-dependent data. Since software logs are also time series, DataTube2 has been enhanced to support the specific data and tasks that are currently found in debugging, yielding to a specific visualization that we called DataTube4log. In this visualization, each line in the tube is devoted to the activity of a thread. Dependencies between threads are materialized with arrows. Synchronization objects are also represented. Using a real dataset, we show how a domain expert has solved a debugging problem. In this experiment, we found that DataTube4log can be easily learned and adopted, and that the ability of the tube to efficiently render an overview of large time series was beneficial to the software engineer.