I’ve recently upgraded my machine from Ubuntu 14.04.4 to Ubuntu 16.04.1, but while my computer used to boot in about 40 seconds, after the upgrade boot times increased considerably to 2 to 3 minutes.
The first easy check was to look at dmesg:
[ 9.776990] usb 3-4.4.2: pl2303 converter now attached to ttyUSB0
[ 11.510201] floppy0: no floppy controllers found
[ 98.444400] vboxdrv: Found 8 processor cores
[ 98.460319] vboxdrv: TSC mode is Invariant, tentative frequency 4026996449 Hz
[ 98.460321] vboxdrv: Successfully loaded version 5.0.26 (interface 0x00240000
There’s a bit 87 seconds gap between checking for the floppy, and VirtualBox drivers loading. So there’s definitely an issue here, but the log does not exactly give a clear queue.
I’ve read you could use systemd-analyze to find which process(es) may be slowing down your computer at boot time:
Two processes are taking close to 8 seconds, but those 16 seconds still do not explain why it takes 2 minutes more to boot…Eventually, I realized systemd-analyze has a few more tricks up its sleeves:
Startup finished in 5.784s (kernel) + 3min 651ms (userspace) = 3min 6.425s
systemd-analyze plot > test.svg
The first command shows there’s no problem with the kernel itself, and something is slow in user space. The second command draws a huge boot chart (SVG), whose shape looks like the picture below.
There are a few things there including the DVDROM drive, and “Prolific Technology Serial Controller” connected to /dev/ttyUSB0. The latter is a USB to TTL debug board based on PL2303, so I removed it and rebooted my machine, and miracle! Boot time was reduced to just 17 seconds:
Startup finished in 5.764s (kernel) + 11.282s (userspace) = 17.047s
systemd-analyze plot > test2.svg
The SVG chart shape, shown on the right, also changed completely as it booted most of the same services in much less time. So since I don’t use the debug board everyday, I’ll make sure I only connect it when needed. Ideally, I suppose a bug should be filled, but I’m not sure which package cause the issue.
On a rather unrelated note, yesterday I also decided to look into Firefox performance issues (switching or closing tabs would take 2 to 3 seconds), and I discovered recent versions of Firefox browser (47+ and greater) include support for “about:performance” tab showing which add-on(s), plugin(s), or page(s) may be problematic. Just let it run for a while, and go about your business browsing the web, and then come back to the tab to check if any has many alerts. It helped me find an add-on slowing down browsing considerably, so I disabled it, and performance is now much better.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.