The size of the buffer used by Performance Analyzer for recording the metrics of individual functions in the call stack is limited. If the size of the call stack becomes so large that the buffer becomes full, any further increase in size of the call stack will force Performance Analyzer to drop function profile information. Because in most programs the bulk of exclusive CPU time is spent in the leaf functions, Performance Analyzer drops the metrics for the less critical functions at the bottom of the stack, starting with the entry functions _start() and main(). The metrics for the dropped functions are consolidated into the single artificial <Truncated-stack> function. The <Truncated-stack> function may also appear in Java programs.
To support deeper stacks, set the SP_COLLECTOR_STACKBUFSZ environment variable to a larger number.