Is anyone else using systemd-bootchart on a system that boots using an initial ramdisk? (e.g. like Fedora 41)
I am fighting with two issues and am looking for some advice. **1. systemd-bootchart stops too early** According to “man systemd-bootchart”, the recommended way to invoke bootchart is via a kernel parameter: init=/usr/lib/systemd/systemd-bootchart That parameter causes systemd-bootchart to be executed as the new init process when we switch into the real root filesystem. bootchart does run, but it stops too early. In /etc/systemd/bootchart.conf, I have bootchart configured to collect 1800 samples at a frequency of 10 samples per sec. It should run for about 3 minutes. When I login, the svg file is already present under /run/log (but the system has only been up for about 10 secs). Doing “grep bootchart /proc/*/cmdline” when I login shows that bootchart is not running. **2. systemd-bootchart errors out during switch root** In this case, I have systemd-bootchart added to the initial ramdisk and execute it via the “rdinit” kernel parameter: rdinit=/usr/lib/systemd/systemd-bootchart In the systemd-bootchart source, you can see that the first character of its argv[0] is changed to “@”, so bootchart should survive the switch-root killing spree. Unfortunately, bootchart errors out during switch root because it wants to read /proc/schedstat and it is not available (I have an strace log confirming that). There seems to be a time-of-check / time-of-use issue in the code -- it checks that the proc filesystem is available, but then when it goes to read /proc/schedstat the file is not there (ENOENT). Has anyone else come across these? Should I open github issues? I can try creating a PR to fix issue 2. Thanks, -James M
