Struct DeadCounter 

#[repr(transparent)]
pub struct DeadCounter(pub u64);

Kernel counter whose update path is permanently dead. The field exists in task_struct (and is exposed via /proc/<tid>/sched) but no kernel writer touches it on any current code path.

Examples that historically motivated this newtype: nr_wakeups_idle, nr_migrations_cold, nr_wakeups_passive — these fields were removed from crate::ctprof::ThreadState because no kernel code path increments them on 6.16 or 7.1 (no schedstat_inc(p->stats.nr_wakeups_idle) / nr_migrations_cold / nr_wakeups_passive call site exists anywhere under kernel/). The newtype remains as infrastructure for future dead counters that get exposed in /proc before (or instead of) being wired up as live counters.

Wire format matches MonotonicCount (u64, serde(transparent)); the capture pipeline parses the same procfs lines and stores the same bits. The type-system difference is in the trait list: a MonotonicCount is Summable / Maxable, while DeadCounter is neither. A registry entry that pairs a DeadCounter field with a Summable-bound AggRule variant fails to compile, flagging the dead status at the type level rather than surfacing as a “0 + 0 + 0” rendered cell.

Migration affordance

A field can be flipped from MonotonicCount to DeadCounter without regenerating any .ctprof.zst snapshot files: the repr(transparent) + serde(transparent) wire format is structurally identical (a bare u64). Existing snapshots deserialize unchanged. The flip changes only the in-memory trait surface, which the registry consumes through AggRule accessors — adjusting those (or removing the field’s registry entry entirely) is the only edit beyond the field type itself.

Defaults to zero. The reduction-trait omission is deliberate: all four reductions (Summable::sum_across, Maxable::max_across, Rangeable::range_across, Modeable::mode_across) on a column of structural zeros trivially produce zero, but rendering that “zero” through a live reduction implies “we measured zero events” when the truth is “we measured a kernel-side dead pointer.” Either add a no-op AggRule variant in the migration batch, or drop these fields from the registry entirely — both are the migration batch’s call.

Tuple Fields

0: u64

Trait Implementations

impl Clone for DeadCounter

fn clone(&self) -> DeadCounter

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DeadCounter

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

Formats the value using the given formatter.

impl Default for DeadCounter

fn default() -> DeadCounter

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for DeadCounter

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for DeadCounter

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

Formats the value using the given formatter.

impl From<DeadCounter> for u64

fn from(v: DeadCounter) -> Self

Converts to this type from the input type.

impl From<u64> for DeadCounter

fn from(v: u64) -> Self

Converts to this type from the input type.

impl Hash for DeadCounter

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 Ord for DeadCounter

fn cmp(&self, other: &DeadCounter) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for DeadCounter

fn eq(&self, other: &DeadCounter) -> 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 PartialOrd for DeadCounter

fn partial_cmp(&self, other: &DeadCounter) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for DeadCounter

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for DeadCounter

impl Eq for DeadCounter

impl StructuralPartialEq for DeadCounter