Help diagnosing lightnig performance issues

Hi there,

On my current machine, opening Lightning’s monthly view takes about 50 seconds. I have 4 calendar subscriptions, with about 50 events.

What’s the right way to profile Thunderbid to find the culprit?


What version of Thunderbird?

68.8.0; I’m on Linux Mint 19.3, which is based on Ubuntu 18.04

Clément, Sorry for the lack of reply.

Performance improvements are beginning, but they will be happening in version 78. So if you are not using the enigmail addon, I would encourage you to update late next week to 78.2.0 from

Hi @wsmwk!

Thanks for your reply. I am now on 78.7.1. The lags are still here; they seem worse than before, but it’s hard to say. When I open the calendar tab, all of Thunderbird freezes for 2 to 5 minutes. This does not happen every time I open the calendar, but it happens very often. Often moving from the mail tab to the calendar tab and back is enough.

Any chance I could help diagnose this locally? With a standard build, the backtraces aren’t exactly useful:

(gdb) bt
#0  0x00007f9ccae4a719 in  () at /usr/lib/thunderbird/
#1  0x00007f9ccae33263 in  () at /usr/lib/thunderbird/
#2  0x00007f9cca9e9d31 in  () at /usr/lib/thunderbird/
#3  0x00007f9ccae37254 in  () at /usr/lib/thunderbird/
#4  0x00007f9ccae36e51 in  () at /usr/lib/thunderbird/
#5  0x00007f9ccae20e86 in  () at /usr/lib/thunderbird/
#6  0x00007f9ccae2295b in  () at /usr/lib/thunderbird/
#7  0x00007f9ccae23a63 in  () at /usr/lib/thunderbird/
#8  0x00007f9ccae24287 in  () at /usr/lib/thunderbird/
#9  0x00007f9ccae144ee in  () at /usr/lib/thunderbird/
#10 0x00007f9ccae02228 in  () at /usr/lib/thunderbird/
#11 0x00007f9ccabd9526 in  () at /usr/lib/thunderbird/
#12 0x00007f9ccac85b92 in  () at /usr/lib/thunderbird/
#13 0x00002994a36a9d6a in  ()
#14 0x00002994a36a3350 in  ()
#15 0x00007ffeb6a38168 in  ()
#16 0x0000393aafd1f100 in  ()
#17 0x0000000000000000 in  ()

OK, I collected a profile:

It looks like Thunderbird is spending 90 seconds in getSubscriptionsDS and 30 seconds in GC, and Thunderbird reports a 104 seconds event-processing delay.

Let me know if I can help further.