Phase 9: Performance
Linux has the richest set of observability tools of any OS. When something is slow, the answer is in the kernel — you just need to know how to ask. From strace for syscall tracing to eBPF for arbitrary kernel instrumentation, these tools let you find bottlenecks without guessing.
What You'll Learn
1. strace
Trace every system call a process makes — the fastest way to debug mysterious slowness.
Intermediate2. perf
CPU profiling, hardware counters, flame graphs — the Swiss army knife of performance.
Advanced3. eBPF
Programmable kernel tracing — observe anything, anywhere, with zero overhead when idle.
Advanced4. ftrace
Kernel function tracer — trace kernel function calls without modifying kernel code.
Advanced5. top & htop
Reading top/htop output correctly — what the columns actually mean.
Beginner6. /proc & /sys Observability
Reading CPU stats, memory pressure, I/O wait, and network counters from the kernel.
Intermediate7. Tracepoints & Probes
Static tracepoints, kprobes, uprobes — attach instrumentation anywhere in kernel or userspace.
Advanced8. dmesg & Ring Buffer
Reading kernel messages, hardware errors, OOM kills, and driver issues from dmesg.
Intermediate