Idle time on tensorboard

I’m new to TF tensorboard. Could you please tell me how GPU idle time is calculated? I see contradictory data in profiling information on tensorboard:

  • I have no blank spaces in events trace (GPU compute stream) presented on trace_viewer page.
  • Wherein device (GPU) idle time shown on tensorflow_stats page is about 50%???

It’s what I see when I use small batch size. After increasing batch size, same situation is on trace_viewer page, but GPU idle time decreased up to 7%. So, how is idle time calculated?

By the way, another two questions:

  1. What is steps on trace_viewer page?
  2. Why does trace_viewer page contain only a part of profiling time? I profiled about 100 seconds of execution, but I see only 10 seconds on trace_viewer page.

Thanks a lot in advance!