Part I — Producer/Consumer with wait/notify (and contrast with busy-wait)

Run with busy-wait (high CPU)

mvn -q -DskipTests exec:java "-Dexec.mainClass=edu.eci.arsw.pc.PCApp \
  -Dmode=spin -Dproducers=1 -Dconsumers=1 -Dcapacity=8 -DprodDelayMs=50 -DconsDelayMs=1 -DdurationSec=30"

Run with monitors (efficient CPU usage)

mvn -q -DskipTests exec:java "-Dexec.mainClass=edu.eci.arsw.pc.PCApp \
  -Dmode=monitor -Dproducers=1 -Dconsumers=1 -Dcapacity=8 -DprodDelayMs=50 -DconsDelayMs=1 -DdurationSec=30"

Scenarios to validate

1. Slow producer / Fast consumer → consumer must wait without CPU when there are no elements.
2. Fast producer / Slow consumer with stock limit → producer must wait without CPU when the queue is full (small capacity, e.g. 4 or 8).
3. Visualize CPU with jVisualVM and compare mode=spin vs mode=monitor.

---

Key Differences: BusySpinQueue vs BoundedBuffer

Aspect	BusySpinQueue (spin)	BoundedBuffer (monitor)
CPU Usage	High (constant spinning)	Low (threads sleep when waiting)
Thread State	RUNNABLE (always)	WAITING/TIMED_WAITING (when idle)
Mechanism	while(true) + Thread.onSpinWait()	synchronized + wait() + notifyAll()
Efficiency	❌ Wastes CPU cycles	✅ Releases CPU when blocked

Evidence Folder

Busy-wait mode (spin) — High CPU

jVisualVM Monitor: High CPU usage with busy-wait

jVisualVM Threads: Threads in RUNNABLE state constantly

Monitor mode (wait/notify) — Efficient CPU

jVisualVM Monitor: Low CPU usage with monitors

jVisualVM Threads: Threads in WAITING state when idle