Android Bootchart log analysis

We're running Android 11 on the custom board. We're using bootchart tool for calculating the Android bootup time. Bootchart logs which are generated after enabling bootchart for which we're not able to generate graphic chart using the command **"pybootchartgui bootchart.tgz"**. We're getting below error when tried to generate the image.

parsing 'bootchart.tgz'
parsing 'header'
parsing 'proc_stat.log'
parsing 'proc_ps.log'
warning: no parent for pid '2' with ppid '0'
parsing 'proc_diskstats.log'
merged 0 logger processes
pruned 222 process, 0 exploders, 2 threads, and 1 runs
False
Traceback (most recent call last):
File "/usr/bin/pybootchartgui", line 23, in
sys.exit(main())
File "/usr/lib/python2.7/dist-packages/pybootchartgui/main.py", line 137, in main
render()
File "/usr/lib/python2.7/dist-packages/pybootchartgui/main.py", line 128, in render
batch.render(writer, res, options, filename)
File "/usr/lib/python2.7/dist-packages/pybootchartgui/batch.py", line 41, in render
draw.render(ctx, options, *res)
File "/usr/lib/python2.7/dist-packages/pybootchartgui/draw.py", line 282, in render
draw_chart(ctx, IO_COLOR, True, chart_rect, [(sample.time, sample.util) for sample in disk_stats], proc_tree)
File "/usr/lib/python2.7/dist-packages/pybootchartgui/draw.py", line 201, in draw_chart
yscale = float(chart_bounds) / max(y for (x,y) in data)
ZeroDivisionError: float division by zero

I searched for other utilities which can analyze bootchart logs, but I couldn't found any. How can I fix the above error or any other method for calculating the bootup time?