ax_task/sched/system/cpu/
load.rs

1/// Scheduler class carried by a remotely observed CPU load summary.
2#[derive(Clone, Copy, Debug, Eq, PartialEq)]
3#[repr(u8)]
4pub enum SchedulingClass {
5    /// Runtime-owned per-CPU stopper work.
6    Stop     = 0,
7    /// Absolute-deadline EDF work.
8    Deadline = 1,
9    /// Fixed-priority FIFO or round-robin work.
10    Realtime = 2,
11    /// EEVDF work: Normal, Batch, and SCHED_IDLE share this class, matching
12    /// Linux's single `cfs_rq`. The per-CPU dedicated idle thread is outside
13    /// every summary class because it is never queued or pushed.
14    Fair     = 3,
15}
16
17/// Allocation-free lockless hints used by remote placement and balancing.
18#[derive(Clone, Copy, Debug, Eq, PartialEq)]
19pub struct CpuLoadSummary {
20    pub(super) queued_count: usize,
21    pub(super) nr_running: usize,
22    pub(super) fair_demand: u64,
23    pub(super) workload_demand: u64,
24    pub(super) current_workload_demand: u64,
25    pub(super) fair_pushable: bool,
26    pub(super) fair_idle_only: bool,
27    pub(super) fair_delayed_count: usize,
28}
29
30/// Per-runqueue GRUB utilization snapshot in billionths of one CPU.
31#[derive(Clone, Copy, Debug, Eq, PartialEq)]
32pub struct DeadlineBandwidthSnapshot {
33    pub(super) this_bw_scaled: u64,
34    pub(super) running_bw_scaled: u64,
35    pub(super) max_bw_scaled: u64,
36}
37
38impl DeadlineBandwidthSnapshot {
39    pub(crate) const fn new(
40        this_bw_scaled: u64,
41        running_bw_scaled: u64,
42        max_bw_scaled: u64,
43    ) -> Self {
44        Self {
45            this_bw_scaled,
46            running_bw_scaled,
47            max_bw_scaled,
48        }
49    }
50
51    /// Returns all Deadline utilization assigned to this runqueue.
52    pub const fn this_bw_scaled(self) -> u64 {
53        self.this_bw_scaled
54    }
55
56    /// Returns ActiveContending plus ActiveNonContending utilization.
57    pub const fn running_bw_scaled(self) -> u64 {
58        self.running_bw_scaled
59    }
60
61    /// Returns utilization currently eligible for GRUB reclaim.
62    pub const fn inactive_bw_scaled(self) -> u64 {
63        assert!(self.running_bw_scaled <= self.this_bw_scaled);
64        self.this_bw_scaled - self.running_bw_scaled
65    }
66
67    /// Returns the per-CPU reclaim capacity.
68    pub const fn max_bw_scaled(self) -> u64 {
69        self.max_bw_scaled
70    }
71}
72
73impl CpuLoadSummary {
74    /// Returns candidates available to `pick_next_task()`, excluding current.
75    pub const fn queued_count(self) -> usize {
76        self.queued_count
77    }
78
79    /// Returns Linux `rq->nr_running`, including a non-idle current task.
80    pub const fn nr_running(self) -> usize {
81        self.nr_running
82    }
83
84    /// Returns the Linux nice-weighted Fair demand owned by this CPU.
85    pub const fn fair_demand(self) -> u64 {
86        self.fair_demand
87    }
88
89    /// Returns instantaneous scheduling demand in normal-nice weight units.
90    ///
91    /// Fair work contributes its exact nice weight. RT and Deadline work each
92    /// contribute one normal-nice capacity unit until class-specific
93    /// utilization tracking is available.
94    pub const fn workload_demand(self) -> u64 {
95        self.workload_demand
96    }
97
98    /// Returns the demand contributed by this CPU's non-idle current task.
99    pub const fn current_workload_demand(self) -> u64 {
100        self.current_workload_demand
101    }
102
103    /// Reports whether this CPU has migratable Fair work.
104    ///
105    /// RT and Deadline overload are deliberately absent from this load
106    /// snapshot. Their sole remote authority is the root-domain `rto`/`dlo`
107    /// index, matching Linux's separation between sched-domain load and
108    /// priority-class overload state.
109    pub const fn has_pushable_fair(self) -> bool {
110        self.fair_pushable
111    }
112
113    /// Reports whether every runnable task on this CPU uses SCHED_IDLE.
114    ///
115    /// Mirrors Linux `sched_idle_rq()`: a non-idle Fair wakee may treat this
116    /// rq as an idle placement target.
117    pub const fn fair_idle_only(self) -> bool {
118        self.fair_idle_only
119    }
120
121    /// Returns Linux `cfs_rq->h_nr_delayed` for this flat runqueue.
122    pub const fn fair_delayed_count(self) -> usize {
123        self.fair_delayed_count
124    }
125}
126
127pub(super) const SUMMARY_FAIR_PUSHABLE: u16 = 1 << 0;
128pub(super) const SUMMARY_FAIR_IDLE_ONLY: u16 = 1 << 1;
ax_task/sched/system/cpu/load.rs

ax_task/sched/system/cpu/
load.rs
