Graphics Register Bus Manager (GRBM)

The Graphics Register Bus Manager (GRBM) exposes coarse-grained utilization for the whole GPU and for individual shader engines (SEs). These counters summarize how busy the graphics/compute complex is; pair them with SPI, WGP, and cache chapters when you need root-cause detail.

The sections below list RDNA3.5 (gfx1151) GRBM-derived utilization tables.

Note

For Instinct-centric shader-engine metrics, see Shader engine (SE).

GPU utilization

RDNA 3.5 (gfx1151)

Metric	Description	Unit
GPU Busy	Percentage of time the GPU was actively processing work. This is the primary utilization metric showing overall GPU activity. Low GPU busy indicates underutilization, possibly due to insufficient workload or host-side bottlenecks.	Percent
CP Busy	Percentage of GPU active time the Command Processor was busy dispatching work and processing commands. High CP busy with low shader activity may indicate dispatch bottlenecks or excessive command stream overhead.	Percent
GL2C Busy	Percentage of GPU active time the GL2 cache was busy servicing memory requests. High GL2 busy indicates memory-intensive workloads. Compare with compute activity to determine if the workload is memory-bound or compute-bound.	Percent

Shader engine utilization

RDNA 3.5 (gfx1151)

Metric	Description	Unit
TA Busy	Percentage of GPU active time the Texture Addresser was busy processing memory address calculations. High TA busy indicates active texture or buffer memory operations. This reflects the address generation workload for memory requests.	Percent