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.
This changes how the AsyncPool works so that it does not immediately always start all of the workers in the pool.
Instead, workers will be started only when an idle worker was not found.
This allows for significant memory footprint reductions while idle.
In effect the async-workers setting in pocketmine.yml now dictates a _maximum_ pool size, not a fixed pool size.
This commit contains quite a few breaking changes with respect to how AsyncTasks are handled. This is necessary to allow separation of the ServerScheduler and the AsyncPool, because in the future the ServerScheduler may be removed and instead there will be isolated per-plugin sync-task schedulers - but we cannot have every plugin with its own worker pool for memory usage reasons if nothing else.
The following things have changed:
- ServerScheduler: scheduleAsyncTask(), scheduleAsyncTaskToWorker(), getAsyncTaskPoolSize(), increaseAsyncTaskPoolSize() and similar methods have all been removed. Additionally the static \$WORKERS field has been removed.
- Server: added API method getAsyncPool(). This grants you direct access to the server's AsyncPool. Calls to getScheduler()->scheduleAsyncTask() and scheduleAsyncTaskToWorker() should be replaced with getAsyncPool()->submitTask() and submitTaskToWorker() respectively.
this implementation was god-awful bad and it was entirely avoidable to make it this complicated.
This utilizes the fact that pthreads treats static properties as thread-local. AsyncTask local storage now utilizes a \SplObjectStorage stored in an AsyncTask private static field.
All plugins will need to bump the API if they want to use this.
NOTE THAT THIS IS NOT THE FINAL API 2.0.0 AND THAT THERE WILL BE MORE CHANGES.
To start updating, you might also want to read https://secure.php.net/manual/en/migration70.php and specifically https://secure.php.net/manual/en/migration70.incompatible.php
To compile PHP7 with some of the required dependencies, use https://gist.github.com/shoghicp/166ab26ce5cc7a390f45
ONLY LINUX IS TESTED, DO NOT ASK FOR OTHER PLATFORMS!
----- THIS VERSION IS NOT SUPPORTED -----
This version WILL crash randomly in unexpected places due to PHP7, pthreads, PocketMine or cosmic rays.
Handle with care, and store under direct sunlight for the best performance.
