Render Command Pipes dedicated asynchronous task pipes for render commands. Users can easily define new pipes and enqueue commands into them. Pipes can be synchronized using a scope to run serial render commands on the render thread, but initially pipes cannot be synchronized individually with each other. Render command overhead is reduced by recording command lambdas into MPSC queues which are serviced by the task graph; both for pipes and for the render thread. This reduces the task overhead as commands are no longer 1-to-1 with tasks.
Pipe behavior is controlled with new CVars. `r.RenderCommandPipeMode` controls overall behavior:
0 - Legacy render thread tasks,
1 - Render thread MPSC queue,
2 - Render thread and async pipe MPSC queues.
To define a Render Command Pipe, use DEFINE_RENDER_COMMAND_PIPE(MyPipe), or DECLARE_RENDER_COMMAND_PIPE(MyPipe, MODULE_API) to declare an extern reference.
Enqueue a command into the pipe like so:
ENQUEUE_RENDER_COMMAND(MyCommand)(UE::RenderCommandPipe::MyPipe, [] (FRHICommandList&) {}).
Omitting a pipe will fallback to the 'general' pipe which is the render thread.
Eventually pipes need to be synced back to the general pipe for scene renders and other GPU work. On the game thread timeline, use UE::RenderCommandPipe::FSyncScope to synchronize the pipes. This waits for pipes and disables recording of new pipe commands until the scope completes, at which point pipe recording is restarted. This creates a 'sync point', so render commands issued prior to a sync scope will be waited on at the start of the scope, and render commands issued after the scope ends will not be able to start until the render thread finishes processing prior commands.
#rb christopher.waters, luke.thatcher
[CL 27074956 by zach bethel in ue5-main branch]
[FYI] zach.bethel
Original CL Desc
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Render Command Pipe Implementation and API
Render Command Pipes dedicated asynchronous task pipes for render commands. Users can easily define new pipes and enqueue commands into them. Pipes can be synchronized using a scope to run serial render commands on the render thread, but initially pipes cannot be synchronized individually with each other. Render command overhead is reduced by recording command lambdas into MPSC queues which are serviced by the task graph; both for pipes and for the render thread. This reduces the task overhead as commands are no longer 1-to-1 with tasks.
Pipe behavior is controlled with new CVars. `r.RenderCommandPipeMode` controls overall behavior:
0 - Legacy render thread tasks,
1 - Render thread MPSC queue,
2 - Render thread and async pipe MPSC queues.
To define a Render Command Pipe, use DEFINE_RENDER_COMMAND_PIPE(MyPipe), or DECLARE_RENDER_COMMAND_PIPE(MyPipe, MODULE_API) to declare an extern reference.
Enqueue a command into the pipe like so:
ENQUEUE_RENDER_COMMAND(MyCommand)(UE::RenderCommandPipe::MyPipe, [] (FRHICommandList&) {}).
Omitting a pipe will fallback to the 'general' pipe which is the render thread.
Eventually pipes need to be synced back to the general pipe for scene renders and other GPU work. On the game thread timeline, use UE::RenderCommandPipe::FSyncScope to synchronize the pipes. This waits for pipes and disables recording of new pipe commands until the scope completes, at which point pipe recording is restarted. This creates a 'sync point', so render commands issued prior to a sync scope will be waited on at the start of the scope, and render commands issued after the scope ends will not be able to start until the render thread finishes processing prior commands.
#rb christopher.waters, luke.thatcher
[CL 27054009 by bob tellez in ue5-main branch]
Render Command Pipes dedicated asynchronous task pipes for render commands. Users can easily define new pipes and enqueue commands into them. Pipes can be synchronized using a scope to run serial render commands on the render thread, but initially pipes cannot be synchronized individually with each other. Render command overhead is reduced by recording command lambdas into MPSC queues which are serviced by the task graph; both for pipes and for the render thread. This reduces the task overhead as commands are no longer 1-to-1 with tasks.
Pipe behavior is controlled with new CVars. `r.RenderCommandPipeMode` controls overall behavior:
0 - Legacy render thread tasks,
1 - Render thread MPSC queue,
2 - Render thread and async pipe MPSC queues.
To define a Render Command Pipe, use DEFINE_RENDER_COMMAND_PIPE(MyPipe), or DECLARE_RENDER_COMMAND_PIPE(MyPipe, MODULE_API) to declare an extern reference.
Enqueue a command into the pipe like so:
ENQUEUE_RENDER_COMMAND(MyCommand)(UE::RenderCommandPipe::MyPipe, [] (FRHICommandList&) {}).
Omitting a pipe will fallback to the 'general' pipe which is the render thread.
Eventually pipes need to be synced back to the general pipe for scene renders and other GPU work. On the game thread timeline, use UE::RenderCommandPipe::FSyncScope to synchronize the pipes. This waits for pipes and disables recording of new pipe commands until the scope completes, at which point pipe recording is restarted. This creates a 'sync point', so render commands issued prior to a sync scope will be waited on at the start of the scope, and render commands issued after the scope ends will not be able to start until the render thread finishes processing prior commands.
#rb christopher.waters, luke.thatcher
[CL 27042459 by zach bethel in ue5-main branch]
- RHICreate{Vertex, Index, Structured}Buffer
- RHICreate{ShaderResource, UnorderedAccess}View
- RHIUpdateUniformBuffer
- Various initialization / locking methods for helper buffer types in RHIUtilities.h
The goal is to continue to force resource creation through command lists to avoid surprises with moving things off the render thread.
#rb christopher.waters
[CL 26183242 by zach bethel in ue5-main branch]
Forcing a tag here is incorrect, as it will override the tag that's supposed to be set by the owner of the resource. For example, this attributed StaticMesh memory to the generic SceneRender tag.
#rb massimo.tristano
#preflight skip
#jira none
#rnx
[CL 25231351 by mihnea balta in ue5-main branch]
Also rename AssetName to OwnerName to better describe what is stored.
#jira UE-167815
#rb Kenzo.Terelst
#preflight 641484d0691c5ebc159b2a5b
[CL 24714010 by Josie Yang in ue5-main branch]
Part3 - Integrate CL23347911 as edigrate
Add owner column to Render Resource Viewer, add owner path name tracking to skeletal & static mesh buffers
with conflict resolve modifications in RawIndexBuffer.cpp/h, RenderResource.cpp/h, RHIResources.h
#preflight 63dab3e2cf5296811729fecd
[CL 23966872 by josie yang in ue5-main branch]
