userspace-resource-manager-extensions

7. Per-App Configuration Guide

File: Configs/PerApp.yaml

Purpose

PerApp.yaml lets you:

Map specific threads of a process to cgroup identifiers.
Declare which resource codes are configurable on a per-app basis.

This allows URM to place high-priority threads into the focused cgroup automatically when a matching process is detected.

Current Configuration

gst-launch- (GStreamer pipelines)

App: gst-launch-
Threads:
  cam-server  -> FOCUSED_CGROUP_IDENTIFIER
  gst-launch- -> FOCUSED_CGROUP_IDENTIFIER

Both the camera server thread and the GStreamer launcher thread are placed in the focused cgroup when a gst-launch- process is detected.

cyclictest (RT workload)

App: cyclictest
Threads:
  cyclictest -> FOCUSED_CGROUP_IDENTIFIER
Configurations: [0x00800001]

The cyclictest thread is placed in the focused cgroup. Resource 0x00800001 (RES_CPU_FREQ_GOV) is configurable per-app for cyclictest.

Schema Reference

Field	Description
App	Substring matched against the process name (from /proc/PID/comm)
Threads	List of thread-name to cgroup-identifier mappings
Configurations	Resource codes that can be tuned per-app for this process

Cgroup Identifiers

Identifier	Cgroup	Description
FOCUSED_CGROUP_IDENTIFIER	Focused (foreground) cgroup	Highest priority; gets most CPU resources

How Thread Matching Works

URM reads /proc/pid/task/tid/comm for each thread of the process. If the thread name contains the configured substring (case-insensitive), the thread is moved to the specified cgroup.

Example: Thread comm: gst-launch-1.0 Config key: gst-launch- Match: YES (substring match)

Adding a New Per-App Config

To add per-app configuration for a new process:

Add an entry to Configs/PerApp.yaml:

PerAppConfigs:
- App: my-app-name Threads:
  - {my-thread: FOCUSED_CGROUP_IDENTIFIER} Configurations: [0x00050003]
Reinstall the configs:

sudo cp Configs/PerApp.yaml /etc/urm/target/ sudo systemctl restart urmserver

Relationship to SignalsConfig

PerApp.yaml works alongside SignalsConfig.yaml:

PerApp.yaml controls which threads get placed in which cgroup.
SignalsConfig.yaml controls what CPU/memory resources are assigned to each cgroup.
Together they ensure the right threads get the right resources.
PerApp.yaml and SignalsConfig.yaml can work independently as well.

For example, when gst-launch-1.0 sends URM_SIG_CAMERA_ENCODE:

PerApp.yaml places gst-launch- and cam-server threads in FOCUSED_CGROUP.
SignalsConfig.yaml assigns all cores + high CPU weight to the focused cgroup.
The camera pipeline threads get maximum CPU access.

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