Severe lag started between r32 and r33

[lucas-mior]

Hello, I recently updated lf after years of not doing so.

I noticed that when navigating (especially on the root directory) lf became extremely unresponsive, in a way that never had happened before. I started downgrading versions, from master to r38 to r37 until r32, where the lag stopped and lf was responsive. Multiple tests show that something happened between r32 and r33.

[joelim-work]

Hi, there's not much to go on here - r33 has quite a large number of changes. It was also released almost a year ago so if there were severe performance issues I imagine there would be other issues raised.

Can this be reproduced with no config file? Was the binary built with Cgo enabled? Is it possible to determine exactly which commit causes this using git bisect?

[lucas-mior]

I just tested with CGO_ENABLED, same result. I will come shortly with more info.

[lucas-mior]

The culprit seems to be my hiddenfiles option:

set hiddenfiles ".*:*.so:*.o:*.pro:*.data:tags:*.bak:*-bak:*-cache:
:*.aux:*.log:*.log:*.loq:*.lot:*.lof:*.bbl:*.bcf:*.blg:*.run.xml:*.toc:
:*.idx:*.bin:*.scout:*.orig:*.synctex:*__pycache__:compile_commands.json"

Commenting it out makes lf smooth again.

[joelim-work]

I searched through the commits between r32 and r33, the only thing I could find related to hiddenfiles was #1684 but I doubt it would be the root cause.

Additionally I tested the above config snippet and didn't notice any lagging. Have you tried using only that hiddenfiles setting as the config file? I'm not sure if that alone is enough to trigger the issue, or if it is in combination with something else.

[lucas-mior]

I used git bisect to identify: e350e0b7352afd3f82da28b91591f597e1dfdc41 is the first bad commit
It seems to be the commit that introduced fsnotify. I tried setting nowatch, but the result is the same. I will do some more testing.

[joelim-work]

OK that's interesting. Commit e350e0b introduces the use of filesystem notifications to detect changes as an alternative to manual polling via the period option. In particular it contains the following changes:

• Addition of the app.setWatchPaths function, which registers the set of directories to be watched, however it does not do anything if the watch option is disabled (default).
• Addition of the app.nav.fileChan channel, which is used to receive updates to files and reload them accordingly.
• Some code was shifted around to make the feature implementation possible.

I can't see how it affects the hiddenfiles option though, except for maybe the part where directories are now sorted after being reloaded.

You can also try inserting some log.Printf("something happened: %v", someVariable) statements at certain points in the code and enable logging to see if there's any code paths that are being hit too often.