Performance collection files like *.etl and *.blg files I work with on a daily basis as a performance consultant. Collecting the files is quite easy, working with them can be teadious. Especially when the log files are seperated (because you don’t want logging to be the bottleneck in the performance and you schedule log creation for once in the x minutes). Because opening the different log files can be very time constraining and not give the entire view of the timeline, I like to merge files.
