wifi/iperf/mcu_host

# Wi-Fi iperf — Host

Wi-Fi throughput benchmark. The Wi-Fi radio runs on the **coprocessor**; the **host** runs the upstream IDF `wifi/iperf` console app, with its `esp_wifi_*` calls routed to the coprocessor over ESP-Hosted. Associate with an AP, then drive TCP/UDP iperf from the console to measure end-to-end throughput across the hosted transport.

`mcu_host/main/iperf_example_main.c` is the upstream IDF `wifi/iperf` example, unchanged; the hosted layer adds only dependency wiring and throughput-tuned host `sdkconfig.defaults`.

## Supported Platforms and Transports

### Supported Coprocessors

| Coprocessor | ESP32 | ESP32-C Series | ESP32-S Series |
| :----------: | :---: | :------------: | :------------: |
| Support     | Yes   | Yes            | Yes            |

### Supported Host Devices

| Host Device | ESP32-P4 | ESP32-H2 | Other MCUs | Linux |
| :---------: | :------: | :------: | :--------: | :---: |
| Support     | Yes | Yes | [Yes](https://github.com/espressif/esp-hosted/blob/master/docs/getting-started-mcu.md) | [Yes](https://github.com/espressif/esp-hosted/blob/master/docs/getting-started-linux.md) |

### Supported Connection buses

| Connection bus | SDIO | SPI Full-Duplex | SPI Half-Duplex | UART |
| :------------- | :--: | :-------------: | :-------------: | :--: |
| Linux host     | Yes  | Yes             | No              | No   |
| MCU host       | Yes  | Yes             | Yes             | Yes  |

## Scenario

The host associates as a Wi-Fi station through the coprocessor, obtains an IP over the hosted netif, then drives iperf/ping from its console to benchmark the link.

```mermaid
sequenceDiagram
    participant App as Host (iperf console)
    participant CP as Co-processor (Wi-Fi)
    participant AP as Access Point / peer
    App->>CP: connect to AP (esp_wifi_* over RPC)
    CP->>AP: associate + authenticate
    App-->>App: IP_EVENT_STA_GOT_IP (got IP)
    App->>AP: iperf -c / -s (TCP/UDP throughput over the hosted transport)
```

Select the transport (must match the co-processor). Wi-Fi credentials are entered at runtime on the console, not in menuconfig:

```bash
cd examples/wifi/iperf/mcu_host
idf.py set-target esp32p4
idf.py menuconfig
```

```text
Component config
└── ESP-Hosted
     └── Configure host
          └── Host transport
               ├── Communication bus (co-processor <== bus ==> host)
               │    ├── ( ) SPI Full Duplex
               │    ├── (X) SDIO                    <── default (match the co-processor)
               │    ├── ( ) SPI Half Duplex
               │    └── ( ) UART
               └── SDIO Configuration               ← slot, bus width, GPIOs (defaults OK)
```

The host dependency + throughput config is **pre-set in `mcu_host/sdkconfig.defaults`** (do not remove):

```text
CONFIG_ESP_HOSTED_HOST_FEAT_RPC=y          # RPC control path to the CP
CONFIG_ESP_HOSTED_HOST_FEAT_RPC_EXT_V2=y   # RPC ext-v2 wire (required)
CONFIG_ESP_HOSTED_HOST_FEAT_SYSTEM=y       # system RPCs
CONFIG_ESP_HOSTED_HOST_FEAT_WIFI=y         # host Wi-Fi feature — routes esp_wifi_* to the CP
```

The defaults also raise Wi-Fi AMPDU windows and LWIP TCP/UDP buffers for throughput — keep them for representative numbers. Then flash and monitor:

```bash
idf.py -p <host_usb_serial_port> flash monitor
```

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