Operating Systems / Linux

Why zero-copy techniques reduce CPU-mediated data movement, with mmap, sendfile, page cache, DMA, and the limits of the term 'zero copy'.

Diagnosing CPU saturation, run queues, context switching, hot code, affinity, and scheduler effects.

Interactive Linux process and host metrics for CPU, memory, load, task state, and quick triage.

Diagnosing resident memory, reclaim, page cache, swap, faults, NUMA, and application allocation behavior.

Sampling runnable/blocked tasks, memory, paging, block I/O, interrupts, context switches, and CPU states.

Diagnosing storage latency, throughput, queueing, cache behavior, filesystem, and application I/O patterns.

Diagnosing latency, throughput, packet loss, retransmission, queues, sockets, connection limits, and kernel networking.

Interpreting CPU and block-device throughput, latency, queueing, and utilization metrics.

An evidence-driven workflow across CPU, memory, disk, network, kernel, and application layers.

Visualizing aggregated stack samples to locate CPU or off-CPU hotspots.