[Interest] QFileSystemWatcher performance (Mac vs. Linux)

René J.V. Bertin rjvbertin at gmail.com
Tue Sep 19 12:04:20 CEST 2017


I've been running into importing slowness in an IDE that I've traced to the creation of a dirwatcher service that monitors the entire source tree for file changes. Creating that service using KF5's KDirWatch has already taken up to about 15 minutes (for the GCC source tree).

KDirWatch *can* use QFileSystemWatcher, and comes with an autotest (kdirwatch_qfswatch_unittest). Comparing timing of that test on a Mac with a 2.7Ghz i7 (and using HFS+) vs. a Linux system with a 1.6Ghz N3150 Celeron (and using ZFS...) shows the Linux system to be roughly 25% faster (20s vs. 15s).

I'm looking for a basic test utility that I can use to benchmark performance (preferable something "done right" to achieve optimum efficiency = not thrown together by me) in order to compare QFileSystemWatcher performance directly, without the KDirWatch overhead. Qt doesn't include an example just for this class, but maybe one exists elsewhere?

Cross-posting this to the Creator ML because the underlying use case is right up their alley.


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