Fixes several files incorrectly stated a different license from the actual project, as well as the copyright headers included in all files. This change has no effect on the licensing terms, it should clear up a bit of confusion by contributors. Plus the files get a bit smaller, and we have less duplicated information across the entire project.
Overall the project is GPLv2 if not built with Qt, and GPLv3 if it is built with Qt. There are no parts licensed under a different license, all have been adapted from other compatible licenses into GPLv2 or GPLv3.
While the previous approach of a static thread pool worked, it was sub-optimal in its resource usage. Many of the threads would never see a single task, and simply permanently sleep. This seems like a good idea, except that sleeping threads still end up in the scheduler, and thus waste a tiny amount of resources.
It is better to instead dynamically spawn threads when needed and only keeping the bare minimum around all the time. These dynamically spawned threads are also explicitly set to background priority which further reduces scheduling overhead. Finally optimizing the memory layout to prevent unwanted false sharing should also keep sporadic wake ups at a minimum.
This new model should be able to handle many more tasks than ever before, but is still not as optimal as it could be.
- Use auto in places where code clarity is improved or identical.
- Replace trivial constructors and destructors with default.
- Use true random for random generation.
- Use std::string_view where it is valid to do so.
- Apply const where it is valid to do so.
- Use references where it is valid to do so.
- Manually optimize memory usage with std::move and std::copy.
- Opt for memory efficient containers where the size is known ahead of time.
Signed-off-by: lainon <GermanAizek@yandex.ru>