On Sat, 2004-11-13 at 12:18 -0500, Owen Taylor wrote: > It should be possible to start with a limited set of easily collected > data and already get a useful picture. Useful data collection could be > as simple as taking a snapshot of the data that the "top" program > displays a few times a second during boot. That already gives you a > list of the running processes, their states, and some statistics about > global system load. So I gave this a try: 1. I modified the boot procedure so that early in rc.sysinit, a tmpfs is mounted and top is run in batch mode (to output every 0.2 seconds). The logged output is later parsed only up to the point where gdmgreeter is running and the system is relatively idle (i.e. boot complete and ready for login). 2. A Java program parses the log file, builds the process tree and finally renders a PNG chart. Processes are sorted by PID and traversed depth first. This still needs more work but here's a sneak preview: http://www.klika.si/ziga/bootchart/bootchart.png (as a result of http://www.klika.si/ziga/bootchart/bootop.log.gz ) Some processes were filtered out for clarity -- mostly sleepy kernel processes and the ones that only live for the duration of a single top sample. This skews the chart a bit but is definitely more comprehensible (compare with http://www.klika.si/ziga/bootchart/bootchart-complete.png ). Some things I plan on adding: - start logging earlier in the boot process (possibly in initrd), - add additional layers (e.g. make use of the kernel patch Arjan suggested for showing the number of open files), - improve process tree representation and add dependency lines, - render SVG instead, for scalability and interactivity. This definitely helped me with my boot times -- the 4-second load gap at the start I found to be "modprobe floppy", apparently timing out on my floppyless laptop :) Any ideas or comments are welcome, -- Ziga
