MVGAL Power Management

Version: 0.5.0

Last Updated: 2026-06-06

Overview
Power Curve System
Idle State Machine
DVFS Control
Gamemode Integration
Thermal Throttling
mvgal-powercurve Tool
Vendor-Specific Power Management

Overview

MVGAL power management operates at two levels:

Kernel-level (kernel/mvgal_power.c, kernel/mvgal_power.h):

Per-GPU DVFS control (frequency/voltage scaling)
Thermal monitoring and throttling
Power budget enforcement

Userspace daemon (runtime/daemon/power_manager.cpp, .hpp):

Power curve management
Idle detection and power gating
Fan curve management
Metrics collection via NVML/hwmon/fdinfo

The kernel module provides the low-level controls; the daemon implements policy. Communication flows through the mvgal_gpu_power struct and IOCTL interface.

Power Curve System

Power curves map GPU workload intensity to power limits, expressed as a percentage of Thermal Design Power (TDP).

Curve Structure

Utilization % → Power Limit % of TDP

A power curve is a table of (utilization, power_limit, temperature_target) points. Linear interpolation is used between points.

Curve Points (Default)

Utilization	Power Limit	Temp Target	Voltage
0%	30%	40°C	Min
25%	50%	55°C	Eco
50%	75%	70°C	Balanced
75%	90%	80°C	Boost
95%	100%	83°C	Max
100%	105%	85°C	Turbo (if available)

Power Curve Profiles

MVGAL ships with four pre-defined profiles:

Profile	Max Power	Temp Target	Use Case
`powersave`	60% TDP	65°C	Quiet, battery
`balanced`	80% TDP	75°C	Default
`performance`	100% TDP	83°C	Gaming
`turbo`	110% TDP	85°C	Benchmarking

mvgal-powercurve --profile performance

Toggle profiles with:

Custom Curves

{
  "profile": "custom",
  "points": [
    {"util": 0, "power": 30, "temp": 40},
    {"util": 30, "power": 60, "temp": 60},
    {"util": 70, "power": 85, "temp": 75},
    {"util": 100, "power": 100, "temp": 82}
  ],
  "fan_curve": "quiet"
}

Users can define custom curves in JSON (/etc/mvgal/powercurve.json):

Idle State Machine

GPUs transition through four power states, defined in runtime/daemon/power_manager.hpp:

          ┌──────────────────────────────────────────────┐
          │                                              │
          ▼                                              │
   ┌──────────┐    timeout    ┌───────────┐              │
   │  ACTIVE  │ ────────────→ │SUSTAINED  │              │
   │  (D0)    │               │  (D0-low)  │              │
   └──────────┘               └───────────┘              │
        ↑                           │                    │
        │                     timeout│                    │
        │                           ▼                    │
        │                    ┌───────────┐    timeout    │
        │                    │   IDLE    │ ─────────────  │
        │                    │  (D3hot)  │                │
        │                    └───────────┘                │
        │                           │                    │
        │                     timeout│                    │
        │                           ▼                    │
        │                    ┌───────────┐               │
        └────────────────────│   PARK    │               │
        activity wakes        │  (D3cold) │               │
                             └───────────┘

State Descriptions

State	Power	Wake Latency	Driver State
`ACTIVE` (D0)	100% TDP	—	Fully operational
`SUSTAINED` (D0-low)	60–80% TDP	< 1 ms	Clocks reduced
`IDLE` (D3hot)	10–30% TDP	10–100 ms	VRAM self-refresh
`PARK` (D3cold)	~0% TDP	100–500 ms	VRAM off, context saved

Transition Timers

Transition	Default Timer	Configurable
ACTIVE → SUSTAINED	5 s idle	Yes (`idle_sustained_ms`)
SUSTAINED → IDLE	30 s idle	Yes (`idle_park_ms`)
IDLE → PARK	120 s idle	Yes (`park_delay_ms`)
Any → ACTIVE	Instant (on activity)	—

DVFS Control

Dynamic Voltage and Frequency Scaling is managed through kernel/mvgal_power.h with support for four DVFS modes:

Mode	Behavior	Use Case
`PERFORMANCE`	Max clock always	Gaming, ML
`BALANCED`	Scale on demand	Default
`POWERSAVE`	Min clock preferred	Battery, idle
`CUSTOM`	User-defined curve	Advanced tuning

Policy Parameters

Each DVFS policy includes:

Parameter	Description	Default
`min_freq_mhz`	Minimum GPU clock	300 MHz
`max_freq_mhz`	Maximum GPU clock	Vendor max
`up_threshold`	Util% to scale up	80%
`down_threshold`	Util% to scale down	30%
`step_delay_ms`	Min interval between changes	50 ms

Querying DVFS State

# Current DVFS mode and frequencies
mvgal-info --dvfs

# Per-GPU power state
mvgal-info --power

Gamemode Integration

MVGAL integrates with Feral Interactive's gamemode daemon.

When Gamemode Is Active

Power profile switches to performance (or turbo if configured).
DVFS mode set to PERFORMANCE.
Idle-state entry timers increased (reduces wake-from-idle latency).
CPU governor hint set to performance.
Fan curve set to active (higher fan speeds, lower temps).

Enabling Gamemode

# Install gamemode
dnf install gamemode

# Enable gamemode daemon
systemctl enable --now gamemoded

# Run a game with gamemode
gamemoderun ./mygame

# Or configure Steam to auto-launch gamemode:
# Settings → Compatibility → Enable gamemode

Configuration

MVGAL-specific gamemode config at /etc/mvgal/gamemode.conf:

[mvgal]
profile=performance
dvfs_mode=PERFORMANCE
idle_sustained_ms=30000
idle_park_ms=60000
fan_curve=active

Thermal Throttling

Thermal management is implemented in kernel/mvgal_power.c with a five-tier state machine defined in runtime/daemon/power_manager.hpp.

Thermal States

State	Temp Range	Action
`NORMAL`	< 75°C	No action
`WARN`	75–85°C	Increase fan speed, log warning
`HOT`	85–92°C	Reduce max clock by 10%
`THROTTLING`	92–100°C	Aggressive clock reduction, power cap
`CRITICAL`	> 100°C	Emergency shutdown (kernel-level)

Throttle Levels

When in THROTTLING state, the kernel applies throttle levels:

Level	Clock Reduction	Power Cap	Duration
1	10%	90% TDP	Until temp < 90°C
2	25%	75% TDP	Until temp < 85°C
3	50%	50% TDP	Until temp < 80°C

Temperature Monitoring

# Current temperatures
mvgal-info --temperature

# Thermal history
mvgal-info --temperature --history

`mvgal-powercurve` Tool

The mvgal-powercurve CLI manages power profiles. Available in tools/.

Commands

Command	Description
`mvgal-powercurve --list`	List available profiles
`mvgal-powercurve --profile <name>`	Set active profile
`mvgal-powercurve --status`	Show current power state
`mvgal-powercurve --fan <speed>`	Manual fan override (0–100)
`mvgal-powercurve --benchmark`	Run power benchmark
`mvgal-powercurve --curve <file>`	Load custom curve from JSON

Example Usage

# Check current state
mvgal-powercurve --status

# Set performance mode
mvgal-powercurve --profile performance

# Load custom curve
mvgal-powercurve --curve ~/my-curve.json

# Run fan at 60%
mvgal-powercurve --fan 60

Vendor-Specific Power Management

NVIDIA

NVML interface: runtime/daemon/nvml_loader.cpp loads NVML dynamically.
Exposed metrics: power draw, temperature, fan speed, clock frequencies.
Supports nvidia-smi-style power limiting.
Dynamic boost on RTX 30xx+.

AMD

hwmon interface: Reads via /sys/class/drm/card/device/hwmon/hwmon/.
Exposed metrics: power draw (via amdgpu hwmon), temperature, fan speed.
amdgpu firmware-based DVFS (no direct clock control from kernel module).

Intel

hwmon interface: Via /sys/class/drm/card/device/hwmon/hwmon/.
Exposed metrics: power draw, temperature (DG2+).
Integrated GPUs share system thermal zone.

Moore Threads

Vendor API: Proprietary MTGX power interface.
Exposed metrics: power draw, temperature (basic).
DVFS support in beta status.

See docs/ARCHITECTURE.md §3—Runtime Daemon for daemon architecture. See runtime/daemon/power_manager.cpp for implementation. See kernel/mvgal_power.c for kernel-level DVFS.