how do I begin in debugging a problem in QBT?

[jointdogg]

Hi guys,
I'm on Qbittorrent 4.1.3, and I have a cpu usage problem:
once every few days, QBT's cpu usage spikes to ~20% and stays there no matter what I do.
closing it and opening again does NOT solve it, I have to restart my PC for it to be down to its usual levels (0.5 to 1 %) again.
I love this client and refuse to replace it - I insist on finding out why this happens.
how can I begin debugging this?
is there a verbose log file somewhere which explains why the client is so busy with CPU? the usual log does not seem to be very active..

p.s. this problem goes all the way back to version 4.0.3 so it is unrelated to the known sandy bridge issue.

thanks!

[Switeck]

qBT for me uses ~25% of my 4 core (4 virtual) i5 CPU if I set the refresh rate in qBT to something silly like 30 ms.

If I break the 127.0.0.1 background connections qBT makes to itself, qBT jumps to >25% CPU usage. This might happen automatically from time-to-time with VPNs that use a kill switch.

[jointdogg]

thanks.
what is this background connection? can you share some details about this?
I don't use vpns, but I noticed it is more likely to happen after/during using acestream/ace player.
also I wanna ask again, is there a more verbose log from qbt? Vuze have an incredible real-time logging option.

[Switeck]

About qBT's background connections:
https://github.com/arvidn/libtorrent/issues/2977

There doesn't seem to be a more verbose log for qBT, but I never looked too deeply into that...so I may be wrong. (might be something different if compiled with debugging options on?)