Debugging Dynamic Memory Usage Errors Using HP WDB (5900-1474; WDB 6.2; January 2011)

The Arenas Block Distribution window displays the block level space distribution
graph for an arena. The graph displays the space occupied by the user blocks, the
free blocks, the unclaimed space, and the malloc metadata (which includes the
node blocks, the cached blocks, the holding header blocks, and the holding SBA
blocks). The virtual address of the blocks is used to arrange the blocks in the graph.
The Block ID of the block is also displayed within the block if the scale of the graph
supports the display. The start of the heap, the end of the heap, the total heap size,
and the total number of blocks are also listed.
WDB GUI displays the block distribution graph in the default window. If the complete
block distribution graph cannot be displayed in the default window, you must select
the Expand Block Distribution Graph toggle option to view the magnified block
distribution graph.
To view the Block ID, the block type, the block size, and the virtual address for each
block in the arena, you must click on the required block in the block distribution
graph. The number of used blocks in each block-count range is also displayed
graphically for the selected arena. This information is also displayed in a tabular
format.
• Heap Arena Space Usage
The Heap Arena Space Usage frame displays the Arena ID, the space usage (in KB)
in the arena, and the percentage space usage in each arena in comparison to the
total space occupied by all the arenas. The comparative space usage across arenas
is also displayed in a pie chart. The Arena ID is also displayed in the pie chart if
the scale of the graph supports it.
• Full Summary
To view the summary for all the arenas, click Full Summary. The summary information
for all the arenas is displayed in the Arena Summary window.
• Heap Arena Detailed Graphs
The Heap Arena Detailed Graphs display the following information:
The byte distribution (in KB) across the used ordinary blocks, the used small blocks,
the free ordinary blocks, and the free small blocks is displayed for each arena. This
information is displayed as a bar graph for each arena.
The byte distribution for the used ordinary blocks, the used small blocks, the free
ordinary blocks, and the free small blocks across the arenas is displayed in a pie
chart. This information is also displayed in a table.
The number of blocks that are distributed across the used ordinary blocks, the used
small blocks, the free ordinary blocks, and the free small blocks are displayed for
each arena. This information is displayed as a bar graph for each arena.
Debugging Memory Using WDB GUI 85