this allows plugins (and maybe later on the core) to detect async worker overload and warn the user about potential performance issues.
I planned to implement such detection in the core directly, but it turned out to be a bit more complex than I anticipated. At the least, this API might be useful to someone else.
This fixes undefined behaviour when scheduling the same task twice. This is usually accidental and almost never desirable.
Note that this still allows a task to be scheduled again after it has
been cancelled; it only disallows scheduling a task multiple times
concurrently.
This commit will probably break MyPlot and other plugins that have
self-scheduling tasks, but as far as I can tell those use-cases should
be replaced with self-cancelling repeating tasks anyway.
this isn't released yet so it's OK to change.
phpstan level 7 doesn't like these kinds of ambiguous return types because there's no way for it to tell which type is returned without a return type specifying extension, and it's easier to just change the API than to make PHPStan understand it.
it's possible that it might not be if the workers were accessed directly, but that shouldn't be possible.
This also silences a PHPStan warning on level 2.
This is better for performance because these then don't need to be reevaluated every time they are called.
When encountering an unqualified function or constant reference, PHP will first try to locate a symbol in the current namespace by that name, and then fall back to the global namespace.
This short-circuits the check, which has substantial performance effects in some cases - in particular, ord(), chr() and strlen() show ~1500x faster calls when they are fully qualified.
However, this doesn't mean that PM is getting a massive amount faster. In real world terms, this translates to about 10-15% performance improvement.
But before anyone gets excited, you should know that the CodeOptimizer in the PreProcessor repo has been applying fully-qualified symbol optimizations to Jenkins builds for years, which is one of the reasons why Jenkins builds have better performance than home-built or source installations.
We're choosing to do this for the sake of future SafePHP integration and also to be able to get rid of the buggy CodeOptimizer, so that phar and source are more consistent.
Since 3.2 there have been some runtime performance issues related to garbage collection and dynamic AsyncWorker booting. This is partly because of GC being dumb about shutting down what it thinks are "unused" workers. A worker which has been idle for a single tick is considered the same as a worker which has been idle for hours. The result of this is that on active servers, workers would get shut down and then immediately restarted because of something like chunk sending. Since booting an async worker is frightfully expensive, this causes lag spikes, which is obviously bad.
This commit changes the GC mechanism to only shutdown workers which have not been used for the last 5 minutes.
