Modrinth
Mod
spark
spark is a performance profiler for Minecraft clients, servers and proxies.
Minecraft product info
Important product information
Compatibility, Minecraft versions, loaders, and external source data.
Type
Mod
Access
Free
Latest version
1.10.173-neoforge
Downloads
21 298 796
Loaders / Platforms
fabric
forge
neoforge
quilt
Minecraft versions
1.16.5
1.17.1 – 1.21.11
26.1
26.1.1
26.1.2
26.2
Categories
utility
Description
Detailed information
#### 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
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## 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)