https://github.com/espressif/esp-idf/issues/8336

main.c

#include <stdio.h>

#include <esp_log.h>
#include <esp_err.h>
#include <driver/gpio.h>
#include <esp32/rom/ets_sys.h>

#include <freertos/FreeRTOS.h>
#include <freertos/event_groups.h>
#include <freertos/semphr.h>
#include <freertos/task.h>

#define RANDOM_SEED 0x1337
#define WAIT_TICKS 1
#define BLINK_BIT 0x1
#define SYNC_BIT 0x2
#define BLINK_GPIO GPIO_NUM_2
#define BLINK_ON 0
#define BLINK_OFF 1

static const char* TAG = "GH8336";

TaskHandle_t task0, task1;
EventGroupHandle_t event_group;
SemaphoreHandle_t sync_semphr;

void init_gpio()
{
  gpio_config_t config = {
    .pin_bit_mask = (1 << BLINK_GPIO),
    .mode         = GPIO_MODE_OUTPUT,
    .pull_up_en   = GPIO_PULLUP_ENABLE,
  };

  ESP_ERROR_CHECK(gpio_config(&config));
}

void task0_main()
{
  for (;;) {
    EventBits_t bits = xEventGroupWaitBits(event_group, BLINK_BIT | SYNC_BIT, pdTRUE, pdFALSE, WAIT_TICKS);

    if (bits & BLINK_BIT) {
      gpio_set_level(BLINK_GPIO, BLINK_ON);
    } else {
      gpio_set_level(BLINK_GPIO, BLINK_OFF);
    }

    if (bits & SYNC_BIT) {
      if (!xSemaphoreGive(sync_semphr)) {
        ESP_LOGE(TAG, "xSemaphoreGive");
        abort();
      }
    }
  }
}

void task1_main()
{
  int count = 0, total_sleep = 0, total_delay = 0, sync_count = 0;

  for (;;) {
    if (++count % 1000 == 0) {
      ESP_LOGI(TAG, "[%04d] sleep=%fms delay=%fus sync=%d",
        count,
        (float)total_sleep / (float)portTICK_RATE_MS,
        (float)total_delay,
        sync_count
      );
    }

    if (rand() % 100) {
      int delay = rand() % 1000;

      ets_delay_us(delay);

      total_delay += delay;
    } else {
      int sleep = rand() % 10;

      vTaskDelay(sleep);

      total_sleep += sleep;
    }

    EventBits_t bits = BLINK_BIT;

    if (xSemaphoreTake(sync_semphr, 0)) {
      sync_count++;
      bits |= SYNC_BIT;
    }

    xEventGroupSetBits(event_group, bits);
  }
}

void app_main(void)
{
  srand(RANDOM_SEED);

  init_gpio();

  if (!(event_group = xEventGroupCreate())) {
    ESP_LOGE(TAG, "xEventGroupCreate");
    abort();
  }

  if (!(sync_semphr = xSemaphoreCreateBinary())) {
    ESP_LOGE(TAG, "xSemaphoreCreateBinary");
    abort();
  }

  xSemaphoreGive(sync_semphr);

  if (!xTaskCreatePinnedToCore(task0_main, "task0", 2048, NULL, 10, &task0, 0)) {
    ESP_LOGE(TAG, "xTaskCreatePinnedToCore");
    abort();
  }

  if (!xTaskCreatePinnedToCore(task1_main, "task1", 2048, NULL, 10, &task1, 1)) {
    ESP_LOGE(TAG, "xTaskCreatePinnedToCore");
    abort();
  }
}