forked from Imagelibrary/rtems
49 lines
1.7 KiB
Perl
49 lines
1.7 KiB
Perl
@c
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@c COPYRIGHT (c) 1988-1998.
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@c On-Line Applications Research Corporation (OAR).
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@c All rights reserved.
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@c
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@c $Id$
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@c
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@chapter Debugging Hints
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The questions in this category are hints that can ease debugging.
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@section How do I determine how much memory is left?
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First there are two types of memory: RTEMS Workspace and Program Heap.
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The RTEMS Workspace is the memory used by RTEMS to allocate control
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structures for system objects like tasks and semaphores, task
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stacks, and some system data structures like the ready chains.
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The Program Heap is where "malloc'ed" memory comes from.
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Both are essentially managed as heaps based on the Heap Manager
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in the RTEMS SuperCore. The RTEMS Workspace uses the Heap Manager
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directly while the Program Heap is actually based on an RTEMS Region
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from the Classic API. RTEMS Regions are in turn based on the Heap
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Manager in the SuperCore.
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@subsection How much memory is left in the RTEMS Workspace?
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An executive workspace overage can be fairly easily spotted with a
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debugger. Look at _Workspace_Area. If first == last, then there is only
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one free block of memory in the workspace (very likely if no task
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deletions). Then do this:
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(gdb) p *(Heap_Block *)_Workspace_Area->first
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$3 = @{back_flag = 1, front_flag = 68552, next = 0x1e260, previous = 0x1e25c@}
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In this case, I had 68552 bytes left in the workspace.
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@subsection How much memory is left in the Heap?
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The C heap is a region so this should work:
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(gdb) p *((Region_Control *)_Region_Information->local_table[1])->Memory->first
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$9 = @{back_flag = 1, front_flag = 8058280, next = 0x7ea5b4,
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previous = 0x7ea5b0@}
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In this case, the first block on the C Heap has 8,058,280 bytes left.
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