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Summary
Fixes sys.cpu.coreUtilization reporting values above 100%, caused by two bugs in ComputeGaugeValues related to how /proc/stat fields were interpreted.
Bug 1: iowait non-monotonicity causing values far above 100%
The iowait field in /proc/stat is documented as non-monotonic on SMP systems — it can decrease between readings. delta_wait was already clamped to 0 when iowait decreased, but delta_total was computed from current.total - prev.total, so the decrease still shrank the denominator. When iowait dropped significantly while other usage stayed constant, delta_total would collapse to near zero while numerators remained large, producing percentages like 5000%.
The fix computes delta_total from the same clamped individual deltas rather than the raw totals, so an iowait decrease no longer affects the denominator.
Bug 2: guest time double-counted
Per /proc/stat semantics, guest and guest_nice time is already included within user and nice respectively. The previous code added guest a second time in both the delta_total denominator (via the total field) and in the usage sum in UpdateCoreUtilization. Because the double-counting occurred in both the numerator and denominator, it did not cause values above 100% — but it did cause percentages to be slightly underreported on systems running VMs. Both have been corrected, and the now-unused Cpu_Gauge_Values::guest field and CpuStatFields::total field have been removed.