mjhjmtu

I want to monitor boot time (the time needed by the system to boot) compared to software version installed (kernel and other software) day by day in order to have a look at boot performance for my arch-linux computer.

I use the systemd command systemd-analyze time to get the boot time.

My idea is to have a log with:

[day]
.......Boot time [s]: 2.145 (kernel) + 13.675 (userspace)
.......with kernel version 4.11.2
.......gnome-shell version 3.24.1
[day+1]
.......Boot time [s]: 3.145 (kernel) + 21.665 (userspace)
.......with kernel version 4.17.11
.......gnome-shell version 3.28.3

How can I do?

Basic idea

I'd be tempted to do this as a systemd service that logs this to a file:

$ systemd-analyze time | sed 's/Startup finished in //;s/ +.*(initrd)//;s/ =.*$//'
442ms (kernel) + 10.224s (userspace)

This cuts the output of systemd-analyze time down to just the bits you want. The rest of the info you want is easy to come by via uname and gnome-shell command-lines' themselves:

$ systemd-analyze time | 
 sed 's/Startup finished in //;s/ +.*(initrd)//;s/ =.*$//'; 
 printf "kernel: %sngnome-shell: %sn" "$(uname -r)" "$(gnome-shell --version)"
442ms (kernel) + 10.224s (userspace)
kernel: 3.10.0-693.21.1.el7.x86_64
gnome-shell: GNOME Shell 3.25.4

More refined

As a script the above:

$ cat ./boottime.bash
#!/bin/bash

printf "[%s]n" "$(date)"
printf ".......Boot time [s]: %sn" "$(systemd-analyze time | sed 's/Startup finished in //;s/ +.*(initrd)//;s/ =.*$//')"
printf ".......with kernel version: %sn" "$(uname -r)"
printf ".......gnome-shell version: %sn" "$(gnome-shell --version)"

#[day]
#.......Boot time [s]: 2.145 (kernel) + 13.675 (userspace)
#.......with kernel version 4.11.2
#.......gnome-shell version 3.24.1
#[day+1]
#.......Boot time [s]: 3.145 (kernel) + 21.665 (userspace)
#.......with kernel version 4.17.11
#.......gnome-shell version 3.28.3

The output:

$ ./boottime.bash
[Sat Aug 4 14:34:40 EDT 2018]
.......Boot time [s]: 442ms (kernel) + 10.224s (userspace)
.......with kernel version: 3.10.0-693.21.1.el7.x86_64
.......gnome-shell version: GNOME Shell 3.25.4

The unit file:

$ cat /etc/systemd/system/boottime.service
[Unit]
Description=Boottime Service
After=systend-user-sessions.service

[Service]
Type=simple
ExecStart=/opt/bin/boottime.bash

TLDR; parsing systemd-analyze time

The sed used above works as follows:

sed 's/Startup finished in //;s/ +.*(initrd)//;s/ =.*$//')"

• 
  s/Startup finished in // - removes everything from left up to the word in
  


• 
  s/ +.*(initrd)// - removes everything starting at + up to (initrd)
  


• 
  s/ =.*$// - removes everything at the end of string, starting with = to the end of the line $