Tag reference

The following is a list of common tags in the MicroProfiler, grouped by category. Tags are also interchangeably called tasks, timers, scopes, processes, and labels. Whatever the name, they represent a unit of work.

Understanding these tags can help you identify problematic code in your game. The tables contain tag label, descriptions, and advice for improving performance and optimizing your game.

Sleep

When threads aren't actively performing tasks, they enter a sleep state, with tags to indicate how long the thread was sleeping. At any given time, it's extremely common for most worker threads to be in a sleep state.

Label	Description	Performance advice
rasterizeTile	Updates navigation tiles needed for a pathfinding request, usually followed by computePath which requires those tiles be up-to-date. Follows NavigationJob/preprocess on the main thread.	Reduce the number of pathfinding tile invalidations, as this causes those paths to need recomputing. This is caused by non-navigable parts moving.
computePath	Calculates paths, typically after rasterizeTile.	Reduce the number and world extents of [`Path:ComputeAsync()`](/docs/path#path-computeasync) calls. Try reusing paths for multiple agents if they are expected to start/end from approximately similar locations.
preprocess/getPrimitivesOverlapping	Collects the world geometry for each pathfinding tile and schedules the rasterization tasks to be executed by the pathfinding thread.	Reduce the part count.

Animation and humanoids

Label	Description	Performance advice
Simulation/gameStepped	Processing of game-specific objects such as [`Humanoids`](/docs/humanoid), [`Animations`](/docs/animation) and heartbeat callbacks.	See gameStepped labels below.
Simulation/gameStepped/stepHumanoid	[`Humanoid`](/docs/humanoid) state changes and movement.	Reduce the amount of [`Humanoids`](/docs/humanoid) or disable [`Humanoid`](/docs/humanoid) states on NPCs that don't need them, such as [`Climbing`](/docs/enum-humanoidstatetype) or [`Swimming`](/docs/enum-humanoidstatetype). Reduce callbacks to [`Humanoid.StateChanged`](/docs/humanoid#humanoid-statechanged) or state changes such as [`Running`](/docs/humanoid#humanoid-running) or [`Died`](/docs/humanoid#humanoid-died).
Simulation/gameStepped/stepAnimation	[`Animators`](/docs/animator) will step forward in currently playing animations.	Reduce the amount of [`Animators`](/docs/animator) or animated joints to lower the workload of this step. Reduce number of callbacks to animation events such as [`AnimationTrack.KeyframeReached`](/docs/animationtrack#animationtrack-keyframereached) or [`AnimationTrack.Ended`](/docs/animationtrack#animationtrack-ended)
Simulation/gameStepped/RunService.Stepped	Runs functions connected to the [`RunService.Stepped`](/docs/runservice#runservice-stepped) event.	Reduce the amount or workload of functions connected to this event. Consider delaying or replacing expensive calculations or spreading computation across multiple frames.

Audio

Label	Description	Performance advice
Sound	Processes acoustic simulation and updates sounds in active playback.	See Sound labels below.
Sound/stepInstances	Updates the volume of active sounds in the workspace.	Reduce the amount of sounds in active playback.

Networking

Label	Description	Performance advice
Net PacketReceive	Receives network packets. If many objects or events are being replicated, this step takes longer.	Replicate fewer objects or events.
Replicator/ProcessPackets	Processes contents of network packets, such as motion, event invocations and property changes.	Reduce the number or size of objects being replicated, or do this in incremental steps. May increase if map size increases, as larger maps tend to have more overall activity.
Allocate Bandwidth and Run Senders/Dispatch Physics Senders and TouchSenders	Sends data about activity in the game.	Reduce the amount of moving objects and/or touches. See following sections.
Allocate Bandwidth and Run Senders/Dispatch StreamJob	Sends corresponding specific regions to specific clients in the streaming feature.	Reduce the minimum and target streaming radii.
Allocate Bandwidth and Run Senders/Dispatch Data Senders	Sends property changes, remote event invocations, [`Humanoid`](/docs/humanoid) state changes, animation state changes, and replication of new instances.	Reduce the number of replicated changes to the data model.
Replicator SendCluster	Sends [Terrain](/docs/roblox-parts-terrain) data to clients.	Reduce the amount or size of terrain changes.
ModelCompleteness Mega Job	Server only: completeness is an internal concept. When models are completely sent, model completeness events are sent.	Add or remove fewer instances.
deserializePacket	Low-level network packet processing. Prepares for Replicator/ProcessPackets.	Send fewer or smaller updates.

Rendering

Label	Description	Performance advice
Prepare	Information is gathered from the main thread and updates various data structures used for rendering.	See Prepare labels below.
Prepare/Pass3dAdorn	Handles rendering of various object adorns, such as text labels above objects. For [`Humanoid`](/docs/humanoid) labels with occlusion, this step includes raycasting to determine if such objects are visible. This includes non-transparent parts to facilitate debug visualizations.	Reduce the number of visible adorned objects, such as [`BillboardGuis`](/docs/billboardgui), [`Humanoid`](/docs/humanoid) name/health labels, etc. Reduce the number of visible parts.
Prepare/Pass2d	Readies 2D UI rendering (both player and Roblox UI).	Reduce the amount or complexity of UI elements.
Prepare/UpdatePrepare/updateInvalidParts	Updates parts that had some property changed or added.	Reduce the amount of properties changes on the world. If a script updates a large set of object properties, break it down across frames.
Prepare/UpdatePrepare/updateInvalidatedFastClusters	Prepares "FastCluster" geometries used to render [`Humanoids`](/docs/humanoid) and [skinned](/docs/roblox-art-modeling-rigging) [`MeshParts`](/docs/meshpart). Labels specify the number of parts, vertices, and size of vertices.	Reduce visual changes to models with [`Humanoids`](/docs/humanoid) or skinned [`MeshParts`](/docs/meshpart).
Prepare/UpdatePrepare/updateDynamicParts	Prepares [`Beams`](/docs/beam), [`ParticleEmitters`](/docs/particleemitter), and [`Humanoids`](/docs/humanoid) for rendering.	Reduce the number of visible [`Beams`](/docs/beam), [`ParticleEmitters`](/docs/particleemitter), and [`Humanoids`](/docs/humanoid).
Prepare/UpdatePrepare/updateInstancedClusters	Updates geometry that uses instanced rendering such as parts. Labels Clusters and Instances indicate the number updated.	Reduce work that implicitly updates the bounding box of the part, such as [`BasePart.CFrame`](/docs/basepart#basepart-cframe), [`BasePart.Size`](/docs/basepart#basepart-size), or [`Motor6D.Transform`](/docs/motor6d#motor6d-transform). Creative property updates such as [`Bone.Transform`](/docs/bone#bone-transform) can help.
Perform	When actual rendering commands are created and issued.	See Perform labels below.
Perform/fillGuiVertices	Fills buffers with UI vertices to prepare for rendering. gui count label indicates the amount of [`LayerCollectors`](/docs/layercollector) visible in the frame.	If the cost is high, reduce the amount, density, and space taken by UI elements. If there are too many Process GuiEffect labels, consider reducing the use of [`UIGradient`](/docs/uigradient) and [`UICorner`](/docs/uicorner) on text labels.
Perform/Scene/queryFrustumOrdered	Applies frustum culling so that objects not visible are not rendered.	If there is a high cost that means there are a lot of elements. Perhaps use some larger meshes where a single mesh has more details as opposed to many small individual pieces.
Perform/Scene/computeLightingPerform	Computation of lighting near the camera.	Manipulate the number of light sources or move the camera less to reduce the time it takes to recalculate lighting.
Perform/Scene/computeLightingPerform/LightGridCPU	Updates the voxel lighting, which is used at lower quality levels.	If updating chunk occupancy takes too long, consider using lower resolution geometry, reducing the number of parts, or anchoring parts. If the other labels take too long, consider reducing the number of lights and using non-shadow casting geometry for objects that move and invalidate the occupancy.
Perform/Scene/computeLightingPerform/ShadowMapSystem	Updates shadow maps. Not performed at quality levels below 4.	Reduce the number of lights. You can also use [`Light.Shadows`](/docs/light#light-shadows) and [`BasePart.CastShadow`](/docs/basepart#basepart-castshadow) to disable shadow casting on less important instances. See [Improve performance](https://create.roblox.com/docs/performance-optimization/improve#mitigation-4).
Perform/Scene/Glow, ColorCorrection, MSAA, SSAO, and SSAOApply	Post-processing rendering.	Reduce the number of post-processing effects. Usually this is not significant.
Perform/Scene/UI	UI rendering. In Id_Screen, there is a label with the number of batches, materials and triangles used.	Reduce the number of visible UI elements. Using [`CanvasGroups`](/docs/canvasgroup) can help at the expense of increased memory use.
Perform/Scene/UpdateView/updateParticles, updateParticleBoundings	Update particle position and bounds.	Reduce the number of [`ParticleEmitters`](/docs/particleemitter), emission rates, lifetimes, etc. Limit the movement of emitters.
Scene/Id_Opaque, RenderView/Id_Opaque	Parts in the scene with an overall transparency of `0.01` or lower.	Reduce the use and density of parts.
Scene/Id_Transparent, RenderView/Id_Transparent	Parts in the scene with an overall transparency between `0.01` and `1`.	Reduce the use of partial transparency.
Scene/Id_Decals, RenderView/Id_Decals	Decals in the scene.	Reduce the use of decals on complex meshes.
Scene/Shadows	Shadow recalculation in the scene, usually performed on dynamic scenes and typical gameplay. Parts regardless of transparency cast shadows under the assumption that they contain decals. Not performed at quality levels below 4.	If this step takes too long, consider disabling [`BasePart.CastShadow`](/docs/basepart#basepart-castshadow) for complex meshes, parts with high partial transparency, and less important instances. Fully transparent parts that don't have decals or need decal shadows should have [`BasePart.CastShadow`](/docs/basepart#basepart-castshadow) disabled. See [Improve performance](https://create.roblox.com/docs/performance-optimization/improve#mitigation-4).
Perform/Present	Forwards to the GPU thread to perform rendering commands.	Reduce scene complexity in general. If this step is taking a long time, you might be limited by the GPU.
Perform/Present/waitUntilCompleted	Waits for the GPU to finish rendering the previous frame.	If this is generally happening a lot then the amount of things rendered is too high. The Frame Rate Manager helps with balancing this, but if it remains high, try following performance advice from the individual Scene tags.
LoadImage	Processes images into a format the engine can use.	Reduce the use of large images.

Scripts

Label	Description	Performance advice
Render/PreRender/fireBindToRenderSteppedCallbacks	Running functions bound to render step via [`RunService:BindToRenderStep()`](/docs/runservice#runservice-bindtorenderstep).	Ensure functions connected to this event do as little work as possible.
Render/PreRender/RunService.RenderStepped	Runs functions connected to the [`RunService.RenderStepped`](/docs/runservice#runservice-renderstepped) event.	Ensure functions connected to this event do as little work as possible.
WaitingHybridScriptJob	Resumes scripts waiting using [`Instance:WaitForChild()`](/docs/instance#instance-waitforchild) or `Globals.Roblox.wait()`. Usually performed 30 times per second. This step has an execution time budget to run waiting scripts.	If you have too many waiting scripts or scripts with a long runtime before yielding, this step is throttled and waits longer before it can run again. Reduce the amount of bound functions or long computations in this step.
GC	Luau's garbage collection cycle.	Pool tables and other collectable objects or try to reduce creating temporary tables.
Heartbeat/RunService.Heartbeat	Runs functions connected to the [`RunService.Heartbeat`](/docs/runservice#runservice-heartbeat) event.	Reduce the amount or workload of functions connected to this event. Consider delaying or replacing expensive calculations or spreading computation across multiple frames.

Simulation

Label	Description	Performance advice
Distributed Physics Ownership	Determines whether the server or a client has authority over certain instances such as parts.	Reduce the amount of parts that frequently switch network ownership, especially those with common interaction.
Simulation/assemble	Updates a tree of connected objects (assemblies) used by the physics engine.	Reduce the amount of joints being created or destroyed.
Simulation/physicsSteppedTotal/physicsStepped	Runs the physics simulation.	Reduce the amount and complexity of physically simulated bodies.
Simulation/physicsSteppedTotal/physicsStepped/SpatialFilter/filterStep	Updates simulation islands, arranging parts according to network ownership, local simulation. Islands are non-interacting groups of parts which can be simulated independently.	Avoid setting network ownership frequently. Keep groups of parts far enough away from each other so they can be simulated separately.
Simulation/physicsSteppedTotal/physicsStepped/worldStep/stepContacts	Updates contacts between objects.	Reduce the amount of bodies colliding at once, or use simpler collision boxes. Cubes are better than complex meshes.
Simulation/physicsSteppedTotal/physicsStepped/worldStep/stepWorld OR stepWorldThrottled	Solves physics equations relating to connectors, buoyancy and [`Humanoids`](/docs/humanoid). When the engine is overloaded and unable to simulate everything in real time, some steps may be throttled (stepWorldThrottled) and only "real-time assemblies" such as [`Humanoids`](/docs/humanoid) are simulated.	Depends on where the time is going based on the following three phases: stepContacts: narrow phase collision detection geometry tests. Solver step: integrate time and resolve collisions and other constraints updateBroadphase: update positions of assemblies in collision detection system and find possibly colliding narrow phase pairs.
notifyMovingAssemblies	Helps track how long primitives have been sleeping.
Simulation/physicsSteppedTotal/physicsStepped/interpolateNetworkedAssemblies	Interpolates assemblies not controlled by the current player.	Set the network owner of parts to the current player to reduce this; although this will usually cause more physics work to be done elsewhere.
Simulation/handleFallenParts	Removes parts that have fallen below [`Workspace.FallenPartsDestroyHeight`](/docs/workspace#workspace-fallenpartsdestroyheight).	Lower the destroy height or reduce the amount of parts that fall to the destroy height.
Heartbeat/heartbeatInternal/workspaceOnHeartbeat/updateVisuallySleeping	Second part of notifyMovingAssemblies.
Heartbeat/RunService.Heartbeat	Runs functions connected to the [`RunService.Heartbeat`](/docs/runservice#runservice-heartbeat) event to simulation and scripts contacts. Current description is generic enough to be not wrong.	Reduce the amount or workload of functions connected to [`RunService.Heartbeat`](/docs/runservice#runservice-heartbeat).
worldStep/stepContacts	Helps physics simulation step many contacts at once.	Reduce the number of colliding objects.
SolveBatch	Helps the physics simulation solve batches of objects' motion.

UI

Label	Description	Performance advice
Render/PreRender/UpdateInput	Updates and fires all user input related events if the user has performed input since the last frame.	Try and not do too much work directly as you get the input. Consider doing a minimal amount of processing for the input, and larger computations should be pushed off to another thread that happens later.
Render/PreRender/TweenService	Updates objects being tweened using [`TweenService`](/docs/tweenservice) and calls completion callbacks, such as those used provided to [`GuiObject:TweenSize()`](/docs/guiobject#guiobject-tweensize) or [`GuiObject:TweenPosition()`](/docs/guiobject#guiobject-tweenposition).	Reduce the number of objects being tweened using [`TweenService`](/docs/tweenservice) and ensure callbacks do as little work as possible.
Heartbeat/TweenService	In the server, [`TweenService`](/docs/tweenservice) runs in [`RunService.Heartbeat`](/docs/runservice#runservice-heartbeat) instead of [`RunService.PreRender`](/docs/runservice#runservice-prerender).	Reduce the number of objects being tweened using [`TweenService`](/docs/tweenservice) and ensure callbacks do as little work as possible.
Render/PreRender/UpdateUILayouts	Updates position and size for UI elements on all enabled [`LayerCollectors`](/docs/layercollector).	See UpdateUILayouts labels below.
Render/PreRender/UpdateUILayouts/Rebuild Z-order list	Rebuilds the internal Z-order list of UI elements (not to be confused with [`GuiObject.ZIndex`](/docs/guiobject#guiobject-zindex)) in a [`LayerCollector`](/docs/layercollector) on first render or when a new element is added, removed, or had its [`GuiObject.ZIndex`](/docs/guiobject#guiobject-zindex) changed.	Reduce the number of UI elements in [`LayerCollectors`](/docs/layercollector) before first render and avoid frequently changing the parent and [`GuiObject.ZIndex`](/docs/guiobject#guiobject-zindex) of UI elements inside them. The more elements a [`LayerCollector`](/docs/layercollector) has, the worse it performs.
Render/PreRender/UpdateUILayouts/Layout	Updates position and size for UI elements in an individual [`LayerCollector`](/docs/layercollector). Can contain a label with information about the relevant UI, along with the amount of Relayouts, Updates and Resizes.	Reduce the amount of UI elements being resized or repositioned, such as those managed by [`UILayout`](/docs/uilayout) and those tweened with [`TweenService`](/docs/tweenservice), [`GuiObject:TweenSize()`](/docs/guiobject#guiobject-tweensize), or [`GuiObject:TweenPosition()`](/docs/guiobject#guiobject-tweenposition). Consider using fixed sizes for [`BillboardGuis`](/docs/billboardgui).