spark

 #### spark is a performance profiler for Minecraft clients, servers and proxies. #### Useful Links * [**Website**](https://spark.lucko.me/) - browse the project homepage * [**Documentation**](https://spark.lucko.me/docs) - read documentation and usage guides * [**Downloads**](https://spark.lucko.me/download) - latest plugin/mod downloads ___ [](https://bisecthosting.com/spark) spark is proudly sponsored by [BisectHosting](https://bisecthosting.com/spark).​ BisectHosting are Minecraft server hosting experts, ready to help you create and host your very own server! They are a trusted and well-established hosting provider in the community, and provide an outstanding level of service that we are happy to recommend. There is a special 25% off discount available for spark users - click the link above to create your server today. ## What does spark do? spark is made up of three separate components: * **CPU Profiler**: Diagnose performance issues. * **Memory Inspection**: Diagnose memory issues. * **Server Health Reporting**: Keep track of overall server health. ### ⚡ CPU Profiler spark's profiler can be used to diagnose performance issues: "lag", low tick rate, high CPU usage, etc. It is: * **Lightweight** - can be ran in production with minimal impact. * **Easy to use** - no configuration or setup necessary, just install the plugin. * **Quick to produce results** - running for just ~30 seconds is enough to produce useful insights into problematic areas for performance. * **Customisable** - can be tuned to target specific threads, sample at a specific interval, record only "laggy" periods, etc * **Highly readable** - simple tree structure lends itself to easy analysis and interpretation. The viewer can also apply deobfuscation mappings. It works by sampling statistical data about the systems activity, and constructing a call graph based on this data. The call graph is then displayed in an online viewer for further analysis by the user. There are two different profiler engines: * Native `AsyncGetCallTrace` + `perf_events` - uses [async-profiler](https://github.com/jvm-profiling-tools/async-profiler) (*only available on Linux x86_64 systems*) * Built-in Java `ThreadMXBean` - an improved version of the popular [WarmRoast profiler](https://github.com/sk89q/WarmRoast) by sk89q. ### ⚡ Memory Inspection spark includes a number of tools which are useful for diagnosing memory issues with a server. * **Heap Summary** - take & analyse a basic snapshot of the servers memory * A simple view of the JVM's heap, see memory usage and instance counts for each class * Not intended to be a full replacement of proper memory analysis tools. (see below) * **Heap Dump** - take a full (HPROF) snapshot of the servers memory * Dumps (& optionally compresses) a full snapshot of JVM's heap. * This snapshot can then be inspected using conventional analysis tools. * **GC Monitoring** - monitor garbage collection activity on the server * Allows the user to relate GC activity to game server hangs, and easily see how long they are taking & how much memory is being free'd. * Observe frequency/duration of young/old generation garbage collections to inform which GC tuning flags to use ### ⚡ Server Health Reporting spark can report a number of metrics summarising the servers overall health. These metrics include: * **TPS** - ticks per second, to a more accurate degree indicated by the /tps command * **Tick Durations** - how long each tick is taking (min, max and average) * **CPU Usage** - how much of the CPU is being used by the server process, and by the overall system * **Memory Usage** - how much memory is being used by the process * **Disk Usage** - how much disk space is free/being used by the system As well as providing tick rate averages, spark can also **monitor individual ticks** - sending a report whenever a single tick's duration exceeds a certain threshold. This can be used to identify trends and the nature of performance issues, relative to other system or game events. ## Usage To install, just add the **.jar** file to your mods directory. Information about [how to use commands](https://spark.lucko.me/docs/Command-Usage) can be found in the docs. If you’d like help analysing a profiling report, or just want to chat, feel free to join us on [Discord](https://discord.gg/PAGT2fu). ## Guides There are a few small "guides" available in the docs, covering the following topics. * [The tick loop](https://spark.lucko.me/docs/guides/The-tick-loop) * [Finding the cause of lag spikes](https://spark.lucko.me/docs/guides/Finding-lag-spikes)