docs(freertos): fixed stack watermark documentation bytes vs words issue

Upstream freertos reports stack sizes in words, while IDF-kernel uses bytes.

Author: ESP-Marius

components/freertos/FreeRTOS-Kernel/include/freertos/task.h

@@ -6,7 +6,7 @@
  *
  * SPDX-License-Identifier: MIT
  *
- * SPDX-FileContributor: 2023-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileContributor: 2023-2025 Espressif Systems (Shanghai) CO LTD
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy of
  * this software and associated documentation files (the "Software"), to deal in
@@ -1493,9 +1493,9 @@ TaskHandle_t xTaskGetHandle( const char * pcNameToQuery ) PRIVILEGED_FUNCTION; /
  * this function to be available.
  *
  * Returns the high water mark of the stack associated with xTask.  That is,
- * the minimum free stack space there has been (in words, so on a 32 bit machine
- * a value of 1 means 4 bytes) since the task started.  The smaller the returned
- * number the closer the task has come to overflowing its stack.
+ * the minimum free stack space there has been in bytes (as opposed to words
+ * in the standard FreeRTOS documentation) since the task started.  The smaller
+ * the returned number the closer the task has come to overflowing its stack.
  *
  * uxTaskGetStackHighWaterMark() and uxTaskGetStackHighWaterMark2() are the
  * same except for their return type.  Using configSTACK_DEPTH_TYPE allows the
@@ -1506,9 +1506,9 @@ TaskHandle_t xTaskGetHandle( const char * pcNameToQuery ) PRIVILEGED_FUNCTION; /
  * @param xTask Handle of the task associated with the stack to be checked.
  * Set xTask to NULL to check the stack of the calling task.
  *
- * @return The smallest amount of free stack space there has been (in words, so
- * actual spaces on the stack rather than bytes) since the task referenced by
- * xTask was created.
+ * @return The smallest amount of free stack space there has been in bytes
+ * (as opposed to words in the standard FreeRTOS documentation) since the task
+ * referenced by xTask was created.
  */
 UBaseType_t uxTaskGetStackHighWaterMark( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;
 
@@ -1518,9 +1518,9 @@ UBaseType_t uxTaskGetStackHighWaterMark( TaskHandle_t xTask ) PRIVILEGED_FUNCTIO
  * this function to be available.
  *
  * Returns the high water mark of the stack associated with xTask.  That is,
- * the minimum free stack space there has been (in words, so on a 32 bit machine
- * a value of 1 means 4 bytes) since the task started.  The smaller the returned
- * number the closer the task has come to overflowing its stack.
+ * the minimum free stack space there has been in bytes (as opposed to words in
+ * the standard FreeRTOS documentation) since the task started.  The smaller the
+ * returned number the closer the task has come to overflowing its stack.
  *
  * uxTaskGetStackHighWaterMark() and uxTaskGetStackHighWaterMark2() are the
  * same except for their return type.  Using configSTACK_DEPTH_TYPE allows the
@@ -1531,9 +1531,9 @@ UBaseType_t uxTaskGetStackHighWaterMark( TaskHandle_t xTask ) PRIVILEGED_FUNCTIO
  * @param xTask Handle of the task associated with the stack to be checked.
  * Set xTask to NULL to check the stack of the calling task.
  *
- * @return The smallest amount of free stack space there has been (in words, so
- * actual spaces on the stack rather than bytes) since the task referenced by
- * xTask was created.
+ * @return The smallest amount of free stack space there has been in bytes
+ * (as opposed to words in the standard FreeRTOS documentation) since the task
+ * referenced by xTask was created.
  */
 configSTACK_DEPTH_TYPE uxTaskGetStackHighWaterMark2( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;
 

docs/en/api-guides/performance/ram-usage.rst

@@ -83,7 +83,7 @@ The Stack Canary Bytes feature adds a set of magic bytes at the end of each task
 Run-time Methods to Determine Stack Size
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-- The :cpp:func:`uxTaskGetStackHighWaterMark` returns the minimum free stack memory of a task throughout the task's lifetime, which gives a good indication of how much stack memory is left unused by a task.
+- The :cpp:func:`uxTaskGetStackHighWaterMark` returns the minimum free stack memory of a task throughout the task's lifetime in bytes, which gives a good indication of how much stack memory is left unused by a task. Note that on {IDF_TARGET_NAME}, the function returns the value in bytes (not words as stated in the standard FreeRTOS documentation).
 
   - The easiest time to call :cpp:func:`uxTaskGetStackHighWaterMark` is from the task itself: call ``uxTaskGetStackHighWaterMark(NULL)`` to get the current task's high water mark after the time that the task has achieved its peak stack usage, i.e., if there is a main loop, execute the main loop a number of times with all possible states, and then call :cpp:func:`uxTaskGetStackHighWaterMark`.
   - Often, it is possible to subtract almost the entire value returned here from the total stack size of a task, but allow some safety margin to account for unexpected small increases in stack usage at runtime.

docs/zh_CN/api-guides/performance/ram-usage.rst

@@ -83,7 +83,7 @@ ESP-IDF 包含一系列堆 API，可以在运行时测量空闲堆内存，请
 任务运行时确定栈内存大小的方法
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-- 调用 :cpp:func:`uxTaskGetStackHighWaterMark` 会返回任务整个生命周期中空闲栈内存的最小值，从而较好地显示出任务未使用的栈内存量。
+- 调用 :cpp:func:`uxTaskGetStackHighWaterMark` 会返回任务整个生命周期中空闲栈内存的最小值（以字节为单位），从而较好地显示出任务未使用的栈内存量。注意：在 {IDF_TARGET_NAME} 上，该函数返回字节数（而不是标准 FreeRTOS 文档中所述的字数）。
 
   - 从任务本身内部调用 :cpp:func:`uxTaskGetStackHighWaterMark` 是调用该函数最容易的方式：在任务达到其栈内存使用峰值后，调用 ``uxTaskGetStackHighWaterMark(NULL)`` 获取当前任务的高水位标记，换言之，如果有主循环，请多次执行主循环来覆盖各种状态，随后调用 :cpp:func:`uxTaskGetStackHighWaterMark`。
   - 通常可以用任务的栈内存总大小减去调用 :cpp:func:`uxTaskGetStackHighWaterMark` 的返回值，计算任务实际使用的栈内存大小，但应留出一定的安全余量，应对运行时栈内存使用量的小幅意外增长。