Spark Mod (26.2, 1.21.1) – Diagnose Your Game's Problems

Spark Mod replicates the functionality of the popular server plugin “Spark” and serves as a profiling tool to identify processes that most affect game or server performance. Simply put, it helps find CPU load sources and processes consuming maximum RAM.

Warning: While the mod is categorized under FPS improvement mods, it doesn’t directly enhance FPS. Instead, it’s a specialized tool for identifying potential problem sources, such as mods causing inefficiencies. Installing it won’t produce immediate results.

This mod is complex and is primarily useful for programmers, as it provides technical insights. However, average users can still use it to analyze CPU loads, memory consumption, and other performance factors.

Features:

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/mod.
• 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 servers 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.

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.

Examples of Usage:

• /spark sampler: Activates CPU load sampling. Use /spark sampler –stop to stop the process, and a link will be provided in the chat to view the collected data.
• /spark heapsummary: Analyzes memory usage and provides a link to view the list of memory-consuming processes, which can help identify problematic mods or items.
• /spark tps: Displays tick rate (TPS) information.
• /spark tickmonitoring: Turns tick rate monitoring on or off.
• /spark heapdump: Creates a memory dump in .hprof format.
• /spark healthreport: Provides server status details, such as average CPU load, average TPS, disk usage, and memory consumption.

Screenshots:

Spark Mod Download Links