The SOF Telemetry subsystem is a suite of built-in diagnostics measuring code execution efficiencies, cycle overheads, and hardware I/O throughput.

Latency and real-time execution bounds are critical in DSP firmware. The telemetry feature provides mechanisms to monitor these bounds accurately without intrusive breakpoints or slowing down the pipeline too aggressively.

Capabilities include:

1. Component Performance Tracking: For every instantiated component in the graph, it measures the pure execution time bounds (min/max/average) of that component's comp_copy() routines.
2. I/O Throughput Tracking: Measures hardware bus speeds or message handling by counting bytes, state changes, or tokens across distinct interfaces: IPC, DMIC, I2S, HD/A, I2C, SPI, etc.
3. Zephyr Systick Measurement: Specifically tracks the overall scheduler overhead bounding RTOS ticks.

Measurements are batched into a ringbuffer locally, then synced across mapped ADSP memory windows into user space, limiting the impact on the active instruction cache.

The architecture bridges the component layer (like pure IPC or Audio Component wrappers) directly into independent statistics accumulators.

graph TD
    subgraph DSP Environment
        Comp[Audio Component X] --> |"comp_copy() Execution"| Telemetry[perf_measure_execute]
        HW[I2S / DMIC HW Driver] --> |"State Change Count"| Telemetry

        Telemetry --> RingBuffer[Statistics Ringbuffer]
        RingBuffer --> Sync["Memory Window 3 (perf_data_sync)"]
    end

    subgraph Host Userspace
        Dev[sof-logger / IPC Tooling] --> |Reads/Queries| Sync
    end

Telemetry depends strictly on NOT being built inside a host-userspace environment simulator (depends on !SOF_USERSPACE_LL). Ensure your target is a physical or emulated DSP target.

Settings to configure in Kconfig:

• CONFIG_SOF_TELEMETRY=y : Enable the overarching telemetry interfaces, giving you systick and basic task metrics over Memory Window 2 interfaces.
• CONFIG_SOF_TELEMETRY_PERFORMANCE_MEASUREMENTS=y : Adds granular tracking to audio components (creating the explicit telemetry.c ringbuffer maps via Memory Window 3 slots). Be aware that only a specific configured amount (PERFORMANCE_DATA_ENTRIES_COUNT) can be actively tracked due to RAM constraints.
• CONFIG_SOF_TELEMETRY_IO_PERFORMANCE_MEASUREMENTS=y : Instructs hardware and communication buses to start pumping data into the metrics collector.

You can fetch these metrics via sof-logger or standard IPC interrogation tools that support polling the corresponding debug window slots mapped for your particular platform's ADSP_MW.