[systemd-devel] Systemd Boot Time Optimization

[Dharma.B at microchip.com]

Hi Everyone,

We have recently migrated from sysvinit to systemd on our platforms,
including sam9, sama5, and sama7 which feature various ARM architectures
such as ARMv5, Cortex-A5, and Cortex-A7.

We observed different performance levels across these architectures,
detailed as follows:

Performance comparison between three architectures using the
core-image-minimal recipe in Yocto Project with a high-speed HP 64GB XC
100MB/s SD card.

*******************************

ARMv5 - sam9

Startup finished in 2.113s (kernel) + 14.090s (userspace) = 16.203s
multi-user.target reached after 14.080s in userspace

Cortex-A5 - sama5

Startup finished in 2.254s (kernel) + 13.216s (userspace) = 15.470s
multi-user.target reached after 13.185s in userspace

Cortex A7 - sama7

Startup finished in 1.967s (kernel) + 6.302s (userspace) = 8.270s
multi-user.target reached after 6.271s in userspace

*******************************

We noted that the following services take significantly longer on the
ARMv5 and Cortex-A5 architectures:

root at sam9x60-curiosity-sd:~# systemd-analyze blame
6.984s dev-mmcblk0p2.device
5.120s systemd-udev-trigger.service
3.063s systemd-networkd.service
1.938s systemd-journald.service
1.850s systemd-timesyncd.service
1.826s systemd-resolved.service
995ms systemd-fsck-root.service

Could you please let us know how to further breakdown the time taken by
"dev-mmcblk0p2.device"

as we don't get anything with

systemd-analyze critical-chain dev-mmcblk0p2.device
The time when unit became active or started is printed after the "@"
character.
The time the unit took to start is printed after the "+" character.

dev-mmcblk0p2.device +6.984s

Is it possible to achieve faster boot times on arm v5 and cortex a5
these architectures similar to cortex a7 by tuning systemd?


Best Regards,
Dharma B.