Delta rollup in Splunk

Hello Team,
I need your guidance to identify delta rollup in Splunk,

  • Delta: For [cumulative counter metrics, the rate is the difference between the data point for the current time interval and the data point for the previous time interval. The Delta rollup is always non-negative; if the value of a cumulative counter data point is smaller than the previous value, the delta is the new value, not the negative difference.
    which is the Prometheus function I can use to achieve delta rollup?
    I tried with the delta function but no luck
    Data resolution and rollups in charts — Splunk Observability Cloud documentation