const (
    // SchedulerSubsystem - subsystem name used by scheduler
    SchedulerSubsystem = "scheduler"
    // SchedulingLatencyName - scheduler latency metric name
    SchedulingLatencyName = "scheduling_duration_seconds"
    // DeprecatedSchedulingLatencyName - scheduler latency metric name which is deprecated
    DeprecatedSchedulingLatencyName = "scheduling_latency_seconds"

    // OperationLabel - operation label name
    OperationLabel = "operation"

    // PredicateEvaluation - predicate evaluation operation label value
    PredicateEvaluation = "predicate_evaluation"
    // PriorityEvaluation - priority evaluation operation label value
    PriorityEvaluation = "priority_evaluation"
    // PreemptionEvaluation - preemption evaluation operation label value (occurs in case of scheduling fitError).
    PreemptionEvaluation = "preemption_evaluation"
    // Binding - binding operation label value
    Binding = "binding"
)

var (

    // PodScheduleSuccesses counts how many pods were scheduled.
    PodScheduleSuccesses = scheduleAttempts.With(metrics.Labels{"result": "scheduled"})
    // PodScheduleFailures counts how many pods could not be scheduled.
    PodScheduleFailures = scheduleAttempts.With(metrics.Labels{"result": "unschedulable"})
    // PodScheduleErrors counts how many pods could not be scheduled due to a scheduler error.
    PodScheduleErrors = scheduleAttempts.With(metrics.Labels{"result": "error"})
    SchedulingLatency = metrics.NewSummaryVec(
        &metrics.SummaryOpts{
            Subsystem: SchedulerSubsystem,
            Name:      SchedulingLatencyName,
            Help:      "Scheduling latency in seconds split by sub-parts of the scheduling operation",

            MaxAge:         5 * time.Hour,
            StabilityLevel: metrics.ALPHA,
        },
        []string{OperationLabel},
    )
    DeprecatedSchedulingLatency = metrics.NewSummaryVec(
        &metrics.SummaryOpts{
            Subsystem: SchedulerSubsystem,
            Name:      DeprecatedSchedulingLatencyName,
            Help:      "Scheduling latency in seconds split by sub-parts of the scheduling operation",

            MaxAge:            5 * time.Hour,
            StabilityLevel:    metrics.ALPHA,
            DeprecatedVersion: "1.14.0",
        },
        []string{OperationLabel},
    )
    E2eSchedulingLatency = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "e2e_scheduling_duration_seconds",
            Help:           "E2e scheduling latency in seconds (scheduling algorithm + binding)",
            Buckets:        metrics.ExponentialBuckets(0.001, 2, 15),
            StabilityLevel: metrics.ALPHA,
        },
    )
    DeprecatedE2eSchedulingLatency = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:         SchedulerSubsystem,
            Name:              "e2e_scheduling_latency_microseconds",
            Help:              "E2e scheduling latency in microseconds (scheduling algorithm + binding)",
            Buckets:           metrics.ExponentialBuckets(1000, 2, 15),
            StabilityLevel:    metrics.ALPHA,
            DeprecatedVersion: "1.14.0",
        },
    )
    SchedulingAlgorithmLatency = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "scheduling_algorithm_duration_seconds",
            Help:           "Scheduling algorithm latency in seconds",
            Buckets:        metrics.ExponentialBuckets(0.001, 2, 15),
            StabilityLevel: metrics.ALPHA,
        },
    )
    DeprecatedSchedulingAlgorithmLatency = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:         SchedulerSubsystem,
            Name:              "scheduling_algorithm_latency_microseconds",
            Help:              "Scheduling algorithm latency in microseconds",
            Buckets:           metrics.ExponentialBuckets(1000, 2, 15),
            StabilityLevel:    metrics.ALPHA,
            DeprecatedVersion: "1.14.0",
        },
    )
    SchedulingAlgorithmPredicateEvaluationDuration = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "scheduling_algorithm_predicate_evaluation_seconds",
            Help:           "Scheduling algorithm predicate evaluation duration in seconds",
            Buckets:        metrics.ExponentialBuckets(0.001, 2, 15),
            StabilityLevel: metrics.ALPHA,
        },
    )
    DeprecatedSchedulingAlgorithmPredicateEvaluationDuration = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:         SchedulerSubsystem,
            Name:              "scheduling_algorithm_predicate_evaluation",
            Help:              "Scheduling algorithm predicate evaluation duration in microseconds",
            Buckets:           metrics.ExponentialBuckets(1000, 2, 15),
            StabilityLevel:    metrics.ALPHA,
            DeprecatedVersion: "1.14.0",
        },
    )
    SchedulingAlgorithmPriorityEvaluationDuration = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "scheduling_algorithm_priority_evaluation_seconds",
            Help:           "Scheduling algorithm priority evaluation duration in seconds",
            Buckets:        metrics.ExponentialBuckets(0.001, 2, 15),
            StabilityLevel: metrics.ALPHA,
        },
    )
    DeprecatedSchedulingAlgorithmPriorityEvaluationDuration = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:         SchedulerSubsystem,
            Name:              "scheduling_algorithm_priority_evaluation",
            Help:              "Scheduling algorithm priority evaluation duration in microseconds",
            Buckets:           metrics.ExponentialBuckets(1000, 2, 15),
            StabilityLevel:    metrics.ALPHA,
            DeprecatedVersion: "1.14.0",
        },
    )
    SchedulingAlgorithmPreemptionEvaluationDuration = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "scheduling_algorithm_preemption_evaluation_seconds",
            Help:           "Scheduling algorithm preemption evaluation duration in seconds",
            Buckets:        metrics.ExponentialBuckets(0.001, 2, 15),
            StabilityLevel: metrics.ALPHA,
        },
    )
    DeprecatedSchedulingAlgorithmPreemptionEvaluationDuration = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:         SchedulerSubsystem,
            Name:              "scheduling_algorithm_preemption_evaluation",
            Help:              "Scheduling algorithm preemption evaluation duration in microseconds",
            Buckets:           metrics.ExponentialBuckets(1000, 2, 15),
            StabilityLevel:    metrics.ALPHA,
            DeprecatedVersion: "1.14.0",
        },
    )
    BindingLatency = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "binding_duration_seconds",
            Help:           "Binding latency in seconds",
            Buckets:        metrics.ExponentialBuckets(0.001, 2, 15),
            StabilityLevel: metrics.ALPHA,
        },
    )
    DeprecatedBindingLatency = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:         SchedulerSubsystem,
            Name:              "binding_latency_microseconds",
            Help:              "Binding latency in microseconds",
            Buckets:           metrics.ExponentialBuckets(1000, 2, 15),
            StabilityLevel:    metrics.ALPHA,
            DeprecatedVersion: "1.14.0",
        },
    )
    PreemptionVictims = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem: SchedulerSubsystem,
            Name:      "pod_preemption_victims",
            Help:      "Number of selected preemption victims",

            Buckets:        metrics.LinearBuckets(5, 5, 10),
            StabilityLevel: metrics.ALPHA,
        })
    PreemptionAttempts = metrics.NewCounter(
        &metrics.CounterOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "total_preemption_attempts",
            Help:           "Total preemption attempts in the cluster till now",
            StabilityLevel: metrics.ALPHA,
        })

    SchedulerGoroutines = metrics.NewGaugeVec(
        &metrics.GaugeOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "scheduler_goroutines",
            Help:           "Number of running goroutines split by the work they do such as binding.",
            StabilityLevel: metrics.ALPHA,
        }, []string{"work"})

    PodSchedulingDuration = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem: SchedulerSubsystem,
            Name:      "pod_scheduling_duration_seconds",
            Help:      "E2e latency for a pod being scheduled which may include multiple scheduling attempts.",

            Buckets:        metrics.ExponentialBuckets(0.001, 2, 15),
            StabilityLevel: metrics.ALPHA,
        })

    PodSchedulingAttempts = metrics.NewHistogram(
        &metrics.HistogramOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "pod_scheduling_attempts",
            Help:           "Number of attempts to successfully schedule a pod.",
            Buckets:        metrics.ExponentialBuckets(1, 2, 5),
            StabilityLevel: metrics.ALPHA,
        })

    FrameworkExtensionPointDuration = metrics.NewHistogramVec(
        &metrics.HistogramOpts{
            Subsystem: SchedulerSubsystem,
            Name:      "framework_extension_point_duration_seconds",
            Help:      "Latency for running all plugins of a specific extension point.",

            Buckets:        metrics.ExponentialBuckets(0.0001, 2, 12),
            StabilityLevel: metrics.ALPHA,
        },
        []string{"extension_point", "status"})

    PluginExecutionDuration = metrics.NewHistogramVec(
        &metrics.HistogramOpts{
            Subsystem: SchedulerSubsystem,
            Name:      "plugin_execution_duration_seconds",
            Help:      "Duration for running a plugin at a specific extension point.",

            Buckets:        metrics.ExponentialBuckets(0.00001, 1.5, 20),
            StabilityLevel: metrics.ALPHA,
        },
        []string{"plugin", "extension_point", "status"})

    SchedulerQueueIncomingPods = metrics.NewCounterVec(
        &metrics.CounterOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "queue_incoming_pods_total",
            Help:           "Number of pods added to scheduling queues by event and queue type.",
            StabilityLevel: metrics.ALPHA,
        }, []string{"queue", "event"})

    PermitWaitDuration = metrics.NewHistogramVec(
        &metrics.HistogramOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "permit_wait_duration_seconds",
            Help:           "Duration of waiting in RunPermitPlugins.",
            Buckets:        metrics.ExponentialBuckets(0.001, 2, 15),
            StabilityLevel: metrics.ALPHA,
        },
        []string{"result"})

    CacheSize = metrics.NewGaugeVec(
        &metrics.GaugeOpts{
            Subsystem:      SchedulerSubsystem,
            Name:           "scheduler_cache_size",
            Help:           "Number of nodes, pods, and assumed (bound) pods in the scheduler cache.",
            StabilityLevel: metrics.ALPHA,
        }, []string{"type"})
)

type MetricRecorder interface {
    Inc()
    Dec()
    Clear()
}

type PendingPodsRecorder struct {
    // contains filtered or unexported fields
}