What is system-level profiling and how is it different from application profiling?

System profiling analyzes OS-level resource usage, while application profiling focuses on code-level performance.

System-level profiling measures CPU scheduling, disk I/O, memory paging, and kernel activity, whereas application profiling measures function execution, call stacks, and memory allocation within an app. System profiling helps detect bottlenecks outside the application scope such as network congestion or disk saturation. Tools include perf, dtrace, and vmstat.