ESP32 Forum

Posted: **Tue May 17, 2022 8:55 am**

Hi,
I have two questions that are related to each other:

1)
After enabling the "run FreeRTOS only on first core" option, I observed the following memory increases:
~51 KB for MALLOC_CAP_EXEC
~17.5 KB for free_heap_size, MALLOC_CAP_DMA, MALLOC_CAP_8BIT, and MALLOC_CAP_DEFAULT

I understand that enabling this option free the cache1 which is 32 KB. However, it does not explain the numbers above totally. Any idea?

2)
I observe the following changes in sdkconfig after enabling only "run FreeRTOS only on first core" :
-CONFIG_BTDM_CTRL_PINNED_TO_CORE_0=y
-CONFIG_BLUEDROID_PINNED_TO_CORE_0=y
-CONFIG_ESP32_WIFI_TASK_PINNED_TO_CORE_0=y
+CONFIG_ESP_SYSTEM_SINGLE_CORE_MODE=y

What does it mean?

Extra: Is there anything that uses cache1 different than freertos?

Posted: **Wed May 18, 2022 11:59 am**

There's a bunch of things that are allocated on a per-core basis. Think interrupt vector tables, coprocessor status pointers etc. You don't need those for the 2nd core if you only use one.

Posted: **Wed May 18, 2022 1:18 pm**

I understand but I use both of the cores. I pin my application tasks to APP_CPU with xTaskCreatePinnedToCore. Other things like wifi, ble runs on PRO_CPU. I only changed the "run FreeRTOS only on first core" option.

Before enabling the "run FreeRTOS only on first core" option:

I (815) psram: This chip is ESP32-D0WD
I (816) spiram: Found 64MBit SPI RAM device
I (816) spiram: SPI RAM mode: flash 40m sram 40m
I (821) spiram: PSRAM initialized, cache is in low/high (2-core) mode.
I (828) cpu_start: Pro cpu up.
I (832) cpu_start: Starting app cpu, entry point is 0x400812fc
0x400812fc: call_start_cpu1 at /home/buraks/esp/esp-idf/components/esp_system/port/cpu_start.c:156

I (0) cpu_start: App cpu up.
I (1717) spiram: SPI SRAM memory test OK
I (1727) cpu_start: Pro cpu start user code

After enabling:

I (807) psram: This chip is ESP32-D0WD
I (808) spiram: Found 64MBit SPI RAM device
I (808) spiram: SPI RAM mode: flash 40m sram 40m
I (813) spiram: PSRAM initialized, cache is in normal (1-core) mode.
I (820) cpu_start: Pro cpu up.
I (824) cpu_start: Single core mode
I (1719) spiram: SPI SRAM memory test OK
I (1729) cpu_start: Pro cpu start user code

I call the following code for many tasks :

Code: Select all

#define PRO_CPU_NUM (0)
#define APP_CPU_NUM (1)
xTaskCreatePinnedToCore(something, "SomeTask", 1024 * 6, NULL, 1, &some_task,  APP_CPU_NUM) ;

So, how can the tasks run on PRO_CPU if they are pinned to APP_CPU?

Thanks in advance.

Posted: **Wed May 18, 2022 1:51 pm**

The answer is they cannot. I'm not sure what the behaviour is if you pin to a core that can't be used; it either may set it to the PRO cpu, run it as unpinned, or not run it at all, I don't remember.

Posted: **Wed May 18, 2022 9:35 pm**

It does default to the pro cpu. If you are not running freertos on the app cpu then you are not using the app cpu.

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Extra memory after "run FreeRTOS only on first core"

Extra memory after "run FreeRTOS only on first core"

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Re: Extra memory after "run FreeRTOS only on first core"