On dinsdag 26 juli 2016 19:44:11 CEST Martin Klapetek wrote: > On Tue, Jul 26, 2016 at 8:03 AM, Sebastian Kügler <se...@kde.org> wrote: > Hey, > > [Please keep both lists addressed.] > > Debugging multiscreen issues is a nightmare: > > - there are at least 4 different processes involved (kded, kcmshell / > systemsettings, kscreen_backend_launcher and plasmashell) > - some are critical during log in > - they IPC with each other > - especially the backend launcher's debug is really hard to get at > > This means that: > - it's hard (almost impossible) for users to get us good and useful logs > - it's hard for ourselves to debug and find out what's exactly going on, > especially when multiple components need to play in tune > > Yesternight, after debugging the so-many-th issue, it occurred to me that we > need to make this way easier to debug. Q(C)Debug falls short in that we get > logs of individual components, if we're lucky. If we're really lucky, we > get timestamps, so we can get a rough idea of what is going down when. > > All of these problems can be solved with a relatively simple, shared log > file. > > So I'd like to switch most of (lib)kscreen's debug output to logging to a > file. The files has then logs from multiple processes and will be much > easier to go through. > > Wouldn't this create a possible concurrency issues when multiple processes > write to the same file? > > What do you think? If you like the idea, I'll polish up my branch and will > post it for review, so we can discuss the actual implementation. > > I think a possible better way could be to log each component into each own > file (in the same dir) with timestamps and function stamps and process > stamps and everything and then merge those files using some automation and > sort by timestamp. Unless Qt on Linux actually handles concurrent write > access just fine and in the correct order (I know it didn't on Windows last > time I looked).
Potentially, yes. Is it a problem? No. The log file isn't critical, and *usually* components are able to write in order (appending to a file doesn't take long). If the log ends up being slightly corrupted, that's bad luck. Instead of implementing complex merging tools or file-locking mechanism, having just these processes write to the same file and cross fingers works well enough. It's a debugging tool, file integrity is just not that important. -- sebas http://www.kde.org | http://vizZzion.org _______________________________________________ Plasma-devel mailing list Plasma-devel@kde.org https://mail.kde.org/mailman/listinfo/plasma-devel
