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linker _user_heap definition may conflict with Arduino IDE RAM calculation #8

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fpistm opened this issue Jun 2, 2017 · 1 comment
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linker _user_heap definition may conflict with Arduino IDE RAM calculation #8

fpistm opened this issue Jun 2, 2017 · 1 comment
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@fpistm
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fpistm commented Jun 2, 2017

From @rogerclarkmelbourne on November 20, 2016 21:52

See http://stm32duino.com/viewtopic.php?f=48&t=1564&p=20198#p20198

@RickKimball posted

The way the arduino IDE calculates RAM usage and the way the linker script attempts to warn you about the low memory usage are in conflict. There are really 1536 bytes of RAM that the linker "allocates" to the heap and the stack. However, the linker's approach doesn't really reflect how much heap or RAM is used. The arduino IDE knows how much RAM a board/chip has and will report low memory issues with a warning about stability. However, neither approach is accurate.

You could probably change the linker script part here from:

 ._user_heap_stack :
   {
     . = ALIGN(4);
     PROVIDE ( end = . );
     PROVIDE ( _end = . );
     . = . + _Min_Heap_Size;
     . = . + _Min_Stack_Size;
     . = ALIGN(4);
   } >RAM

to:

 ._user_heap_stack :
  {
  . = ALIGN(4);
 PROVIDE ( end = . );
 PROVIDE ( _end = . );
 } >RAM

This would stop the reporting of a bogus RAM memory usage and in our case, the arduino IDE will start complaining if you are getting too close to the edge.

Copied from original issue: fpistm/Arduino_Core_STM32L4#6
@fpistm fpistm mentioned this issue Jun 2, 2017
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@fpistm fpistm added the question ❓ Usually converted as a discussion label Jun 15, 2017
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fpistm commented Jan 29, 2018

Closed as no question/issue raised linked to this

@fpistm fpistm closed this as completed Jan 29, 2018
fpistm referenced this issue in fpistm/Arduino_Core_STM32 Feb 14, 2018
@fpistm
Removed ._user_heap_stack section from the Arduino reported RAM usage
f0e24bf 
Linker script defined ._user_heap_stack section to check that there
is enough RAM left.
Arduino should not report this but only the real one used.

Example for a BluePill:
.user_heap_stack section is equal to 1536 (_Min_Heap_Size+_Min_Stack_Size)
If used to compute RAM usage of blink sketch, Arduino reports: 2456 bytes
While it is not computed, it reports 916 bytes (=2456-1536-4(align))

Linker always ensures there is enough space defined thanks .user_heap_stack
Arduino will report real size and will warn if sketch use more than the
default RAM usage (build.warn_data_percentage=75)

See #8

Signed-off-by: Frederic.Pillon <frederic.pillon@st.com>
fpistm added a commit that referenced this issue Mar 6, 2018
@fpistm
Removed ._user_heap_stack section from the Arduino reported RAM usage
34a87b0 
Linker script defined ._user_heap_stack section to check that there
is enough RAM left.
Arduino should not report this but only the real one used.

Example for a BluePill:
.user_heap_stack section is equal to 1536 (_Min_Heap_Size+_Min_Stack_Size)
If used to compute RAM usage of blink sketch, Arduino reports: 2456 bytes
While it is not computed, it reports 916 bytes (=2456-1536-4(align))

Linker always ensures there is enough space defined thanks .user_heap_stack
Arduino will report real size and will warn if sketch use more than the
default RAM usage (build.warn_data_percentage=75)

See #8

Signed-off-by: Frederic.Pillon <frederic.pillon@st.com>
@rayozzie rayozzie mentioned this issue Aug 20, 2018
Closed
@DarXSouls DarXSouls mentioned this issue Mar 29, 2019
Closed
benwaffle pushed a commit to benwaffle/Arduino_Core_STM32 that referenced this issue Apr 10, 2019
@fpistm
Removed ._user_heap_stack section from the Arduino reported RAM usage
73d4c67 
Linker script defined ._user_heap_stack section to check that there
is enough RAM left.
Arduino should not report this but only the real one used.

Example for a BluePill:
.user_heap_stack section is equal to 1536 (_Min_Heap_Size+_Min_Stack_Size)
If used to compute RAM usage of blink sketch, Arduino reports: 2456 bytes
While it is not computed, it reports 916 bytes (=2456-1536-4(align))

Linker always ensures there is enough space defined thanks .user_heap_stack
Arduino will report real size and will warn if sketch use more than the
default RAM usage (build.warn_data_percentage=75)

See stm32duino#8

Signed-off-by: Frederic.Pillon <frederic.pillon@st.com>
fpistm pushed a commit that referenced this issue Aug 13, 2021
@sabas1080
Merge pull request #8 from stm32duino/master
8d7c806 
Update 7/08/2021
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