One of the offeners is

vyos@vyos# show system config-management commit-archive
 location tftp://172.16.20.200/CONFIGS/BR1.wueIII

removing this line will reduce the boot time to 700 seocnds (down by 30%) .. weird

0-18 kernel boot
18-41 system starting inc FRR
70-120 the python most of the time is spend/wasted in cli-shell-api - so I would think reading the configuration file. If we can optimise / reduce this number of calls it would be very good.
140-220 is more or less firewall setup with vyatta-firewall / vyatta-upset.pl / ip6tables

rounding numbes:

So 22% in cli-shell-api
So 36% in firewall

Please see attached the full log of the boot process. I try to supply a PNG later on but I guess it will be really huge.

Every call to /bin/cli-shell-api --show-working-only --show-show-defaults --show-ignore-edit showConfig takes multiples seconds (6?)
/usr/libexec/vyos/conf_mode/system-timezone.py call it twice.
/usr/libexec/vyos/conf_mode/nat.py call it twice
/usr/libexec/vyos/conf_mode/interfaces-loopback.py call it twice ... etc.

Looking at the ... seconds it takes to set the hostname ...
The code for /usr/libexec/vyos/conf_mode/host_name.py is spent waiting for vyos-hostd to come back

sudo apt install python3-pip
sudo pip3 install -U pip setuptools wheel virtualenv
pip3 install git+https://github.com/evanhempel/python-flamegraph.git
python3 -m flamegraph -o perf.log /usr/libexec/vyos/conf_mode/host_name.py
./flamegraph.pl perf.log > unix-time.svg

https://docs.google.com/document/d/1pKkxwq5eBm9eSTmyrSluDU1cx8NYqQRkQNdTB1tCSdk/edit?usp=sharing

Why is it sometimes called twice?

Possibly it's in cases where it's first called in get_config(), then also later in verify() or apply() - the object is function local scope and isn't saved in a global variable. It would be a simple fix if Config() were initialised in main() and passed as an argument to any function that needs it.

I've created some proof of concept code that i think could help on this issue. https://github.com/runborg/vyos-1x/blob/main-cfg/src/conf_mode/main.py this is a conf-mode executor that handles multiple conf mode scripts. The reason i think this could seriously help on this issue is that as this is all running inside a single python tnterpreter, its able to load the config object once and pass it to all needed conf_mode scripts without a need for reinitialization.

The only big bottleneck with this script is that it only executes as a single vyatta-cfg priority so all executed scripts needs to be in a continous order without old bash dependencies.

As the current "priority map" there aren't a loot of concurrent python blocks, but i think many of the remaining bash/perl scripts could be moved to new places. https://pastebin.com/z6ZvkJKB

I used @runar code on my branch working on T2522 .. Configuring 100 dummy interface went from 42 to 8 seconds.

Sorry, but I dont think this is fixed; I just attempted to upgrade my working 1.2.8 configuration to 1.3.

The 1.2.8 configuration will (eventually, after a very long time) fail with an out-of-memory condition when attempting to load on 1.3.

[  812.814956] Out of memory: Killed process 1348 (python3) total-vm:3779656kB, anon-rss:3425936kB, file-rss:1808kB, shmem-rss:0kB, UID:0 pgtables:6784kB oom_score_adj:0
[  813.965717] vyos-router[813]: Starting VyOS router: migrate rl-system firewall configure/usr/libexec/vyos/init/vyos-router: line 104:  1348 Killed                  sg ${GROUP} -c "$vyos_libexec_dir/vyos-boot-config-loader.py $BOOTFILE"
[  814.089133] vyos-router[813]:  failed!

This is under KVM, so I just doubled the memory (from 4G to 8G) and tried. It takes longer, but eventually bombs. Watching in virt-top shows memory usage slowly increasing:

667221 libvirt+  20   0   10.6g   8.1g  28044 S 137.7   1.6  48:39.51 qemu-sy+

On 1.2.8, the exact same configuration loaded in just about 5 minutes. I'm still waiting for the login prompt on 1.3 now, after ~20 minutes. Have to fall back to 1.2.8, unfortunately, perhaps I might try a 1.4 rolling when I get back from holiday.