ESP32-S3使用tcp_server例程，并将网络数据和串口数据透传延迟过高

[Eltrion]

使用tcp_server例程修改，将tcp数据与串口数据进行透传，串口→tcp的数据延迟很低，基本都在10ms以内，但是tcp→串口的数据延迟就很高，会达到100ms以上，回环测试的延迟也在60ms以上，通过逻辑分析仪抓取到大部分时间耗费在recv函数上，请问下这种问题是在idf里普遍存在的还是我的工程设置有问题或者环境原因？但是在使用modbus TCP例程的时候，返回数据的延迟却特别低，基本都在5ms以内。
以下是代码，工程由v5.1创建

Code: Select all

/* BSD Socket API Example

   This example code is in the Public Domain (or CC0 licensed, at your option.)

   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/
#include <string.h>
#include <sys/param.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include "esp_netif.h"
#include "protocol_examples_common.h"

#include "lwip/err.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include <lwip/netdb.h>

#include "driver/uart.h"
#include "driver/gpio.h"

#define PORT                        CONFIG_EXAMPLE_PORT
#define KEEPALIVE_IDLE              CONFIG_EXAMPLE_KEEPALIVE_IDLE
#define KEEPALIVE_INTERVAL          CONFIG_EXAMPLE_KEEPALIVE_INTERVAL
#define KEEPALIVE_COUNT             CONFIG_EXAMPLE_KEEPALIVE_COUNT

static const char *TAG = "example";

int tcp_sock = 0;

QueueHandle_t uart_queue = NULL;

static void do_retransmit(const int sock)
{
    int len;
    char rx_buffer[128];

    do {
        len = recv(sock, rx_buffer, sizeof(rx_buffer) - 1, 0);
        if (len < 0)
        {
            ESP_LOGE(TAG, "Error occurred during receiving: errno %d", errno);
        }
        else if (len == 0)
        {
            ESP_LOGW(TAG, "Connection closed");
        } 
        else
        {
            uart_write_bytes(UART_NUM_1, rx_buffer, len);
            rx_buffer[len] = 0; // Null-terminate whatever is received and treat it like a string
            ESP_LOGI(TAG, "Received %d bytes: %s", len, rx_buffer);
            
            int to_write = len;
            while (to_write > 0) {
                int written = send(sock, rx_buffer + (len - to_write), to_write, 0);
                if (written < 0) {
                    ESP_LOGE(TAG, "Error occurred during sending: errno %d", errno);
                    // Failed to retransmit, giving up
                    return;
                }
                to_write -= written;
            }
        }
    } while (len > 0);
}

static void tcp_server_task(void *pvParameters)
{
    char addr_str[128];
    int addr_family = (int)pvParameters;
    int ip_protocol = 0;
    int keepAlive = 1;
    int keepIdle = KEEPALIVE_IDLE;
    int keepInterval = KEEPALIVE_INTERVAL;
    int keepCount = KEEPALIVE_COUNT;
    struct sockaddr_storage dest_addr;

#ifdef CONFIG_EXAMPLE_IPV4
    if (addr_family == AF_INET) {
        struct sockaddr_in *dest_addr_ip4 = (struct sockaddr_in *)&dest_addr;
        dest_addr_ip4->sin_addr.s_addr = htonl(INADDR_ANY);
        dest_addr_ip4->sin_family = AF_INET;
        dest_addr_ip4->sin_port = htons(PORT);
        ip_protocol = IPPROTO_IP;
    }
#endif
#ifdef CONFIG_EXAMPLE_IPV6
    if (addr_family == AF_INET6) {
        struct sockaddr_in6 *dest_addr_ip6 = (struct sockaddr_in6 *)&dest_addr;
        bzero(&dest_addr_ip6->sin6_addr.un, sizeof(dest_addr_ip6->sin6_addr.un));
        dest_addr_ip6->sin6_family = AF_INET6;
        dest_addr_ip6->sin6_port = htons(PORT);
        ip_protocol = IPPROTO_IPV6;
    }
#endif

    int listen_sock = socket(addr_family, SOCK_STREAM, ip_protocol);
    if (listen_sock < 0) {
        ESP_LOGE(TAG, "Unable to create socket: errno %d", errno);
        vTaskDelete(NULL);
        return;
    }
    int opt = 1;
    setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
#if defined(CONFIG_EXAMPLE_IPV4) && defined(CONFIG_EXAMPLE_IPV6)
    // Note that by default IPV6 binds to both protocols, it is must be disabled
    // if both protocols used at the same time (used in CI)
    setsockopt(listen_sock, IPPROTO_IPV6, IPV6_V6ONLY, &opt, sizeof(opt));
#endif

    ESP_LOGI(TAG, "Socket created");

    int err = bind(listen_sock, (struct sockaddr *)&dest_addr, sizeof(dest_addr));
    if (err != 0) {
        ESP_LOGE(TAG, "Socket unable to bind: errno %d", errno);
        ESP_LOGE(TAG, "IPPROTO: %d", addr_family);
        goto CLEAN_UP;
    }
    ESP_LOGI(TAG, "Socket bound, port %d", PORT);

    err = listen(listen_sock, 1);
    if (err != 0) {
        ESP_LOGE(TAG, "Error occurred during listen: errno %d", errno);
        goto CLEAN_UP;
    }

    while (1) {

        ESP_LOGI(TAG, "Socket listening");

        struct sockaddr_storage source_addr; // Large enough for both IPv4 or IPv6
        socklen_t addr_len = sizeof(source_addr);
        int sock = accept(listen_sock, (struct sockaddr *)&source_addr, &addr_len);
        if (sock < 0) {
            ESP_LOGE(TAG, "Unable to accept connection: errno %d", errno);
            break;
        }

        tcp_sock = sock;

        // Set tcp keepalive option
        setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, &keepAlive, sizeof(int));
        setsockopt(sock, IPPROTO_TCP, TCP_KEEPIDLE, &keepIdle, sizeof(int));
        setsockopt(sock, IPPROTO_TCP, TCP_KEEPINTVL, &keepInterval, sizeof(int));
        setsockopt(sock, IPPROTO_TCP, TCP_KEEPCNT, &keepCount, sizeof(int));
        // Convert ip address to string
#ifdef CONFIG_EXAMPLE_IPV4
        if (source_addr.ss_family == PF_INET) {
            inet_ntoa_r(((struct sockaddr_in *)&source_addr)->sin_addr, addr_str, sizeof(addr_str) - 1);
        }
#endif
#ifdef CONFIG_EXAMPLE_IPV6
        if (source_addr.ss_family == PF_INET6) {
            inet6_ntoa_r(((struct sockaddr_in6 *)&source_addr)->sin6_addr, addr_str, sizeof(addr_str) - 1);
        }
#endif
        ESP_LOGI(TAG, "Socket accepted ip address: %s", addr_str);

        do_retransmit(sock);

        shutdown(sock, 0);
        close(sock);
    }

CLEAN_UP:
    close(listen_sock);
    vTaskDelete(NULL);
}

void diaodian()
{

}

void uart_read_task(void *arg)
{
    uart_event_t event;
    uint8_t uart_data[1024] = {0};

    while (1)
    {
        if(xQueueReceive(uart_queue, (void*)&event, portMAX_DELAY))
        {
            //接收到串口数据
            memset(uart_data, 0, sizeof(uart_data));
            switch (event.type)
            {
            case UART_DATA:
                ESP_LOGI(TAG, "串口数据事件");
                uart_read_bytes(UART_NUM_1, uart_data, event.size, portMAX_DELAY);  //接收串口数据
                send(tcp_sock, uart_data, event.size, 0);   //发送数据到网口
                break;
            
            default:
                ESP_LOGI(TAG, "其他串口事件，事件类型：%d", event.type);
                break;
            }
        }
    }

    vTaskDelete(NULL);
}


void app_main(void)
{
    uart_config_t uart_cfg = {
        .baud_rate = 115200,
        .parity = UART_PARITY_DISABLE,
        .stop_bits = UART_STOP_BITS_1,
        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
        .source_clk = UART_SCLK_DEFAULT,
    };
    uart_driver_install(UART_NUM_1, 2 * 1024, 2 * 1024, 10, &uart_queue, 0);
    uart_param_config(UART_NUM_1, &uart_cfg);
    uart_set_pin(UART_NUM_1, GPIO_NUM_4, GPIO_NUM_5, -1, -1);
    xTaskCreate(uart_read_task, "read_task", 5 * 1024, NULL, 3, NULL);
    
    ESP_ERROR_CHECK(nvs_flash_init());
    ESP_ERROR_CHECK(esp_netif_init());
    ESP_ERROR_CHECK(esp_event_loop_create_default());

    /* This helper function configures Wi-Fi or Ethernet, as selected in menuconfig.
     * Read "Establishing Wi-Fi or Ethernet Connection" section in
     * examples/protocols/README.md for more information about this function.
     */
    ESP_ERROR_CHECK(example_connect());

#ifdef CONFIG_EXAMPLE_IPV4
    xTaskCreate(tcp_server_task, "tcp_server", 4096, (void*)AF_INET, 5, NULL);
#endif
#ifdef CONFIG_EXAMPLE_IPV6
    xTaskCreate(tcp_server_task, "tcp_server", 4096, (void*)AF_INET6, 5, NULL);
#endif
}

下图是串口与tcp透传的时间

以下是使用modbus TCP例程的延迟时间

[ralfak]

应该是无线网的问题，你ping一下试试，一来一回都是上百ms，而且wifi这个东西是半双工的

[Eltrion]

应该是无线网的问题，你ping一下试试，一来一回都是上百ms，而且wifi这个东西是半双工的

你好，我同时也试了不使用wifi，使用esp32s2+w5500通过有线以太网建立tcp服务器，延迟也基本是在60-100ms，连续发送数据的话延迟会更高，ping的延迟是2ms以内。