Tornado

Tornado 2.0
User’s Guide
6.12.2 Stack Overflow
When a task exceeds its stack size, the resulting problem is often hard to trace,
because the initial symptom may be in some other task altogether. The browser’s
stack-check window is useful when faced with behavior that is hard to explain: if
the problem is a stack overflow, you can spot it immediately. The affected task’s
stack display shows a high-water mark at the right edge, as in the example in
Figure 6-22.
Figure 6-22
Stack Overflow on Task u9
6.12.3 Memory Fragmentation
A more subtle memory-management problem occurs when small blocks of
memory that are not freed for long periods are allocated interleaved with
moderate-sized blocks of memory that are freed more frequently: memory can
become fragmented, because the calls to free( )for the large blocks cannot coalesce
the free memory back into a single large available-memory pool. This problem is
easily observed by examining the affected memory partition (in simple
applications this is the VxWorks system memory partition, memSysPartId) with
the browser. Figure 6-23 shows an example of a growing free-list with many small
blocks, characteristic of memory fragmentation.
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