spark in All the Mods 10

spark is a performance profiler for Minecraft clients, servers and proxies. If your world lags, your tick rate drops or memory use climbs, this is the tool that helps you find out why. It adds no blocks, items or machines, so there is nothing to craft or place.^[1]

This pack ships spark 1.10.124 as the NeoForge build, and it has been part of the pack since version 2.25 or earlier.^[2]

What it does

• CPU Profiler: diagnoses performance problems such as lag, low tick rate and high CPU usage. It is lightweight, needs no setup, and running for about 30 seconds is enough to give useful results. You can tune it to target specific threads, set a sampling interval, or record only the laggy periods.^[1]
• Memory Inspection: includes a heap summary, a full heap dump you can open in conventional analysis tools, and garbage collection monitoring that lets you relate GC activity to hangs.^[1]
• Server Health Reporting: tracks TPS, tick durations, CPU usage, memory usage and disk usage. It can also report whenever a single tick takes longer than a threshold you choose.^[1]

Profiler results are built as a call graph and shown in an online viewer, where the simple tree layout makes them easy to read.^[1]

Who it is for

It is for server owners and for any player who wants to track down lag spikes or memory trouble in a big modpack. Because it works on clients, servers and proxies, you can use it in single-player as well as on a hosted server. It is also handy when you are asking for help, since a profiler report shows exactly where the time is going.^[1]

Where it fits in progression

spark is a diagnostic utility, so it does not fit into a progression chain. You can use it from the very start of a world, and nothing needs to be unlocked first.^[1]

Unverified The sources I was given show no quests involving spark and no place for it on the ATM Star path, so I can't say anything about either.

spark is a little different from most mods you'll meet in this pack. It's a performance profiler for Minecraft clients, servers and proxies, so there's nothing to build or progress through. It's a diagnostic tool you reach for when the game starts to lag.^[1]

The profiler is described as easy to use, with no configuration or setup necessary. The order below is how I'd approach it when something feels off.^[1]

What to check, in order

1. Start with server health. spark can report TPS, tick durations (min, max and average), CPU usage, memory usage and disk usage. This tells you whether there's a problem at all, and what kind.^[1]
2. If you're seeing lag, low tick rate or high CPU usage, run the CPU profiler. Running it for just about 30 seconds is enough to give useful insights into problem areas.^[1]
3. Read the results as a call graph. spark samples statistical data about system activity, builds a call graph from it, and shows it in an online viewer. The simple tree structure makes it easy to interpret.^[1]
4. If the problem looks memory-related, use the memory tools. A heap summary gives you a basic snapshot of memory usage and instance counts per class. A heap dump takes a full HPROF snapshot for conventional analysis tools. GC monitoring lets you relate garbage collection activity to game hangs.^[1]

The profiler can also be tuned to target specific threads, sample at a specific interval, or record only laggy periods. It has two engines: a native async-profiler engine that is only available on Linux x86_64 systems, and a built-in Java ThreadMXBean engine.^[1]

Unverified I couldn't confirm anything pack-specific for this mod. That includes the exact commands and permission levels in this pack, any config changes, and any crafting recipes or quests tied to it. Check in-game before relying on specifics.

Here's the thing about spark: it isn't a tech or machine mod. There are no machines, multiblocks, power networks, fluid pipes or item automation to set up. It's a performance profiler for Minecraft clients, servers and proxies, so "core mechanics" here means the diagnostic tools it gives you.^[1]

The sources also don't list any items or crafting recipes for it, so you won't be crafting anything with this mod.^[1]

The three components

• CPU Profiler: diagnoses performance issues such as lag, low tick rate and high CPU usage.^[1]
• Memory Inspection: diagnoses memory issues.^[1]
• Server Health Reporting: keeps track of overall server health.^[1]

How the CPU profiler works

The profiler samples statistical data about system activity and builds a call graph from it. That graph is then shown in an online viewer, where you can analyse it as a simple tree structure. The viewer can also apply deobfuscation mappings.^[1]

It's described as lightweight enough to run in production with minimal impact. Running it for just about 30 seconds is enough to give useful insight into problem areas. You can also tune it to target specific threads, sample at a specific interval, or record only "laggy" periods.^[1]

There are two profiler engines. One uses the native AsyncGetCallTrace plus perf_events through async-profiler, and it's only available on Linux x86_64 systems. The other is the built-in Java ThreadMXBean engine, an improved version of the WarmRoast profiler.^[1]

Memory tools

• Heap Summary: a basic snapshot of the JVM's heap, showing memory usage and instance counts for each class. It isn't meant to replace proper memory analysis tools.^[1]
• Heap Dump: a full HPROF snapshot of the server's memory, optionally compressed, which you can open in conventional analysis tools.^[1]
• GC Monitoring: watches garbage collection activity so you can relate it to server hangs, see how long collections take and how much memory they free, and compare young and old generation collections to help choose GC tuning flags.^[1]

Server health reporting

spark can report TPS (ticks per second, to a more accurate degree than the /tps command), tick durations (min, max and average), CPU usage for the server process and the overall system, memory usage, and disk usage.^[1]

Besides tick rate averages, it can monitor individual ticks and send a report whenever a single tick's duration exceeds a certain threshold. That helps you spot trends and the nature of a performance problem relative to other system or game events.^[1]

Configuration in this pack

The pack sets backgroundProfiler to false in its spark config file. The file's header _header points to spark's own configuration documentation.^[3]

Unverified What the backgroundProfiler option does in detail isn't explained in the available sources, so check spark's official configuration documentation before relying on it.

The quest chapter available for this guide is "Ice and Fire", with 87 quests. The quests shown in it ask for items from Ice and Fire and from vanilla Minecraft, and none of them asks for an item from spark. Because of that, there is no spark quest path or tier ladder I can describe for you.^[4]

Unverified Where spark sits in the pack's quest book, and whether it has any tiers or upgrade steps, is not shown by the sources here. No in-pack recipes produce this mod's items, and the mod is not on the ATM Star quest path. If you want to know whether the quest book mentions it, check the quest book in game.

The pack's quest book has an Ice and Fire chapter with 87 quests and an Iron's Spells 'n Spellbooks chapter with 103. In the quests shown for those two chapters, the tasks ask for items from Minecraft, Ice and Fire and Iron's Spells 'n Spellbooks, or for visiting a biome, structure or dimension, or killing a mob. None of them asks for anything from spark, so no quest to list for it was found.^[4][5]

Unverified 79 of the 103 quests in the Iron's Spells 'n Spellbooks chapter, and the whole Productive Trees chapter, are not shown in the sources here, so it can't be confirmed what they ask for. Check those chapters in the quest book yourself.

Good news: spark is a simple one to configure. It's a performance profiler for clients, servers and proxies, and the project describes its CPU profiler as needing no configuration or setup, so you can just install it and go. This pack's config file is tiny.^[1][3]

What the pack sets

• backgroundProfiler is set to false in this pack. It is the only setting in the file.^[3]
• _header is just a text note at the top of the file that points to spark's configuration documentation. It doesn't change any behavior.^[3]

The sources I have for spark only cover a small slice of its history in the pack, so this section is short on purpose.^[2][6]

• spark has been in the pack since All the Mods 10 2.25 or earlier, so it's a long-standing part of the modpack.^[2]
• In All the Mods 10 2.37, the pack updated spark from 1.10.109 to 1.10.124.^[6]
• All the Mods 10 8.1 ships spark 1.10.124 (the NeoForge jar), which is the same version the 2.37 update brought in.^[2][6]

Unverified I don't have stored changelogs for the shipped spark jars, so what changed between 1.10.109 and 1.10.124 inside the mod itself is unverified. Any pack updates to spark between 2.37 and 8.1 are also not covered by my sources.