RAPL
Overview
RAPL (Running Average Power Limit) is an Intel processor feature that allows real-time energy consumption measurements of CPU and memory subsystem.
This technology has been available on Intel processors since Sandy Bridge generation.
RAPL provides energy measurements at different scales (e.g.,CPU core, integrated GPU, package), enabling you to measure energy consumption per component and understand more precisely how each part of the system contributes to the overall power usage.
Architecture
RAPL interface exposes multiple power domains that allow measuring energy consumption of different parts of the processor and memory subsystem. Domains metrics are accessible through model-specific registers (MSRs) on the host system, enabling user to monitor power usage in real time.
Domains
| Domain | Description |
|---|---|
| Package/PKG | Entire CPU socket. This includes cores and uncore components. |
| Core/PP0 | Represents the CPU cores only. Useful for profiling per-core energy consumption. |
| Uncore/PP1 | Covers the energy consumption of the integrated GPU if available. |
| DRAM | Dynamic random access memory attached to the integrated memory controller if supported. |
| PSYS | Entire SoC energy consumption, unique (only one PSYS for the entire SoC at most, available since Skylake generation) |
Architecture of RAPL1:
Note
- Some of the domains may not appear depending on the processor architecture.
- The PSYS domain can report the same consumption as an external wattmeter 1, representing the entire computer consumption. These results, obtained on a laptop, should be interpreted with caution and could not reflect the real world.