Power Management
Why are temperature sensors often placed at many locations within a large chip?
- AMore sensors cool the chip
- BTemperature sensors can be used only once
- CAreas such as dense arithmetic units heat up locally (hot spots), so a single sensor cannot reveal the hottest point
Show answer and explanation
Answer: C. Areas such as dense arithmetic units heat up locally (hot spots), so a single sensor cannot reveal the hottest point
Power usage varies greatly across a chip, and active cores or arithmetic units can run tens of degrees hotter than cache regions. Temperature limits are set by the hottest spot, so a single sensor might miss a hot spot reaching a dangerous temperature. Sensors are placed at many locations, and frequency control or throttling is based on the highest reading.
- A. Sensors do not cool anything.
- B. Sensors work repeatedly.
- C. Correct. Control is based on the hottest spot.