[GSD-12906] `zesPowerGetEnergyCounter()` returns near-zero energy values periodically on idle Intel Arc Pro B70/B60 — possible counter wrap

[sjlealru]

Environment

Node	GPU SKU	Kernel	compute-runtime (libze-intel-gpu1)	L0 loader (libze1)	TW spikes
node-A	B70 (0x8086:E223)	6.17.0-35-generic	26.09.37435.12	1.28.0	49
node-C	B70 (0x8086:E223)	6.17.0-1009-intel	26.09.37435.12	1.28.0	2
node-D	B60	6.14.0-1011-intel	25.40.35563.10	1.26.2	17
node-B	B70 (0x8086:E223)	6.17.0-1009-intel	26.18.38308.1	1.28.2	0

OS: Ubuntu 24.04 | xpumanager: 1.3.5-20251216 | Monitoring: 54 hrs, all nodes idle (0% GPU util)

Observed behavior

zesPowerGetEnergyCounter() periodically returns energy values of ~100–300 J on GPU cards that have been continuously idle. The sysfs hwmon energy*_input counter for the same card at the same moment continues accumulating normally, confirming the hardware energy is intact.

xpumd reads the L0 counter every ~5s and computes power as ediff / tdiff. When the counter drops to ~200 J from ~22 MJ, the subtraction underflows as uint64, producing a ~3.69 TW result reported via hw_power_watts.

Captured values at spike moment

Time (UTC)	GPU (BDF)	zesPowerGetEnergyCounter (L0, power-1)	sysfs energy1_input	hw_power_watts
2026-06-09 19:44:10	node-A 0001:6b:00.0	209.8 J	22,543,283.9 J	3,688,785,853,643 W
2026-06-09 22:02:11	node-A 0001:91:00.0	173.4 J	23,329,654.5 J	3,690,483,216,906 W

Statistics (54-hour window)

• L0 counter resets: 345
• TW spike events: 68
• sysfs counter drops (node-C only): 67

Related: intel/xpumanager#130