My first instinct was to reach for a simple stack per thread, which is fine as a starting point, but the inlining part tripped me up.
Start by clarifying requirements and constraints, then outline a high-level architecture covering sampling, stack reconstruction, and aggregation. Dive into the algorithmic challenges of handling inlined and tail-called functions, and discuss trade-offs in data structures and performance.
Pro tip: Emphasize that accurate stack reconstruction requires combining runtime sampling with static binary analysis (e.g., DWARF debug info) to resolve inlining and tail calls, and that aggregation should use a space-efficient trie with incremental updates to handle high-frequency samples.
Ask about sampling frequency, overhead tolerance, supported platforms, and whether real-time or offline analysis is needed. Confirm the output format for hot stacks.
Describe how to collect instruction pointers and thread IDs at regular intervals using OS timers or performance counters, ensuring minimal overhead and thread safety.
Explain how to unwind stacks from sampled IPs, handling inlined functions via debug info and tail calls by analyzing control flow. Mention fallback strategies like frame pointers or DWARF CFI.
Propose a data structure (e.g., trie or hash map) to aggregate stack traces per thread, and describe how to compute and report the hottest stacks efficiently.
Cover trade-offs between accuracy and overhead, memory usage, and sampling frequency. Suggest optimizations like sampling only on CPU cycles or using lock-free data structures.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.