Enum BpfMapAgg 

pub enum BpfMapAgg {
    Scalar,
    ScalarCounter,
    PerCpu,
    PerCpuCounter,
}

Aggregation for a WatchBpfMap target.

Picks how a watched field’s per-tick reads collapse into run-level metric key(s). Choose by the field’s semantic class: a GAUGE (a current level — fold as the mean) vs a monotonic COUNTER (an accumulating total — fold as the final value).

Variants

Scalar

A single scalar GAUGE field (e.g. a .bss global struct member like sys_stat.avg_lat_cri — a current level such as latency-criticality or headroom). Emits ONE metric key (<prefix>_<label>), folded as the mean over the run’s reporting samples. For a monotonic counter use BpfMapAgg::ScalarCounter instead — a rising counter mean-folded here reports a window-average below its final total.

ScalarCounter

A single scalar monotonic COUNTER field (e.g. a .bss global like ktstr_alloc_count bumped via __sync_fetch_and_add). Emits ONE metric key (<prefix>_<label>), folded as the value at the LAST reporting sample — the accumulated total at the end of the monitoring window, which is the meaningful count (not the mean of a rising series).

PerCpu

A per-CPU array field (a BPF_MAP_TYPE_PERCPU_ARRAY value member, e.g. cpu_ctx_stor.lat_headroom). Emits TWO metric keys: the cross-CPU mean (<prefix>_<label>_avg) and the cross-CPU spatial max (<prefix>_<label>_max), each folded over the run’s reporting samples. The divisor is the count of CPUs that reported a value, never the topology CPU count.

PerCpuCounter

A per-CPU array field that is a monotonic COUNTER (each CPU’s slot rises independently, e.g. a BPF_MAP_TYPE_PERCPU_ARRAY per-CPU event tally). Emits ONE metric key (<prefix>_<label>), folded as the CROSS-CPU SUM at the LAST reporting sample — the accumulated total across all (reporting) CPUs at the end of the monitoring window, and SUM-folded across runs like BpfMapAgg::ScalarCounter. Watch at u64 width: a too-narrow width truncates each per-CPU slot before the sum. An offline CPU’s accumulated count is excluded (only CPUs whose per-CPU page is readable contribute). Use this for a rising per-CPU counter; BpfMapAgg::PerCpu mean/max-folds (a gauge) and BpfMapAgg::ScalarCounter is for a single scalar, not a per-CPU array.

Trait Implementations

impl Clone for BpfMapAgg

fn clone(&self) -> BpfMapAgg

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BpfMapAgg

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for BpfMapAgg

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for BpfMapAgg

fn eq(&self, other: &BpfMapAgg) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for BpfMapAgg

impl Eq for BpfMapAgg

impl StructuralPartialEq for BpfMapAgg