Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type DispatchingConfig ¶ added in v0.18.0
type DispatchingConfig struct {
// ConcurrencyLimit is the maximum number of requests of this QueueSet that may be executing at a time
ConcurrencyLimit int
// ConcurrencyDenominator is used in relative metrics of concurrency.
// It equals ConcurrencyLimit except when that is zero.
ConcurrencyDenominator int
}
DispatchingConfig defines the configuration of the dispatching aspect of a QueueSet.
type Integrator ¶ added in v0.19.0
type Integrator interface {
fcmetrics.Gauge
GetResults() IntegratorResults
// Return the results of integrating to now, and reset integration to start now
Reset() IntegratorResults
}
Integrator computes the moments of some variable X over time as read from a particular clock. The integrals start when the Integrator is created, and ends at the latest operation on the Integrator.
func NewNamedIntegrator ¶ added in v0.26.0
func NewNamedIntegrator(clock clock.PassiveClock, name string) Integrator
NewNamedIntegrator makes one that uses the given clock and name
type IntegratorResults ¶ added in v0.19.0
type IntegratorResults struct {
Duration float64 //seconds
Average float64 //time-weighted
Deviation float64 //standard deviation: sqrt(avg((value-avg)^2))
Min, Max float64
}
IntegratorResults holds statistical abstracts of the integration
func (*IntegratorResults) Equal ¶ added in v0.19.0
func (x *IntegratorResults) Equal(y *IntegratorResults) bool
Equal tests for semantic equality. This considers all NaN values to be equal to each other.
type Moments ¶ added in v0.19.0
type Moments struct {
ElapsedSeconds float64 // integral of dt
IntegralX float64 // integral of x dt
IntegralXX float64 // integral of x*x dt
}
Moments are the integrals of the 0, 1, and 2 powers of some variable X over some range of time.
func ConstantMoments ¶ added in v0.19.0
ConstantMoments is for a constant X
func (Moments) AvgAndStdDev ¶ added in v0.19.0
AvgAndStdDev returns the average and standard devation
type QueueNoteFn ¶ added in v0.19.0
type QueueNoteFn func(inQueue bool)
QueueNoteFn is called when a request enters and leaves a queue
type QueueSet ¶
type QueueSet interface {
// BeginConfigChange starts the two-step process of updating the
// configuration. No change is made until Complete is called. If
// `C := X.BeginConstruction(q)` then `C.Complete(d)` returns the
// same value `X`. If the QueuingConfig's DesiredNumQueues field
// is zero then the other queuing-specific config parameters are
// not changed, so that the queues continue draining as before.
// In any case, reconfiguration does not discard any queue unless
// and until it is undesired and empty.
BeginConfigChange(QueuingConfig) (QueueSetCompleter, error)
// IsIdle returns a bool indicating whether the QueueSet was idle
// at the moment of the return. Idle means the QueueSet has zero
// requests queued and zero executing. This bit can change only
// (1) during a call to StartRequest and (2) during a call to
// Request::Finish. In the latter case idleness can only change
// from false to true.
IsIdle() bool
// StartRequest begins the process of handling a request. If the
// request gets queued and the number of queues is greater than 1
// then StartRequest uses the given hashValue as the source of
// entropy as it shuffle-shards the request into a queue. The
// descr1 and descr2 values play no role in the logic but appear
// in log messages. This method always returns quickly (without
// waiting for the request to be dequeued). If this method
// returns a nil Request value then caller should reject the
// request and the returned bool indicates whether the QueueSet
// was idle at the moment of the return. Otherwise idle==false
// and the client must call the Finish method of the Request
// exactly once.
StartRequest(ctx context.Context, width *request.WorkEstimate, hashValue uint64, flowDistinguisher, fsName string, descr1, descr2 interface{}, queueNoteFn QueueNoteFn) (req Request, idle bool)
// Dump saves and returns the instant internal state of the queue-set.
// Note that dumping process will stop the queue-set from proceeding
// any requests.
// For debugging only.
Dump(includeRequestDetails bool) debug.QueueSetDump
}
QueueSet is the abstraction for the queuing and dispatching functionality of one non-exempt priority level. It covers the functionality described in the "Assignment to a Queue", "Queuing", and "Dispatching" sections of https://github.com/kubernetes/enhancements/blob/master/keps/sig-api-machinery/1040-priority-and-fairness/README.md . Some day we may have connections between priority levels, but today is not that day.
type QueueSetCompleter ¶ added in v0.18.0
type QueueSetCompleter interface {
// Complete returns a QueueSet configured by the given
// dispatching configuration.
Complete(DispatchingConfig) QueueSet
}
QueueSetCompleter finishes the two-step process of creating or reconfiguring a QueueSet
type QueueSetFactory ¶
type QueueSetFactory interface {
// BeginConstruction does the first phase of creating a QueueSet.
// The RatioedGaugePair observes number of requests,
// execution covering just the regular phase.
// The denominator for the waiting phase is
// max(1, QueuingConfig.QueueLengthLimit) X max(1, QueuingConfig.DesiredNumQueues).
// The RatioedGauge observes number of seats occupied through all phases of execution.
// The denominator for all the ratioed concurrency gauges is supplied later in the DispatchingConfig.
// The Gauge observes the seat demand (executing + queued seats).
BeginConstruction(QueuingConfig, metrics.RatioedGaugePair, metrics.RatioedGauge, metrics.Gauge) (QueueSetCompleter, error)
}
QueueSetFactory is used to create QueueSet objects. Creation, like config update, is done in two phases: the first phase consumes the QueuingConfig and the second consumes the DispatchingConfig. They are separated so that errors from the first phase can be found before committing to a concurrency allotment for the second.
type QueuingConfig ¶ added in v0.18.0
type QueuingConfig struct {
// Name is used to identify a queue set, allowing for descriptive information about its intended use
Name string
// DesiredNumQueues is the number of queues that the API says
// should exist now. This may be non-positive, in which case
// QueueLengthLimit, HandSize, and RequestWaitLimit are ignored.
// A value of zero means to respect the ConcurrencyLimit of the DispatchingConfig.
// A negative value means to always dispatch immediately upon arrival
// (i.e., the requests are "exempt" from limitation).
DesiredNumQueues int
// QueueLengthLimit is the maximum number of requests that may be waiting in a given queue at a time
QueueLengthLimit int
// HandSize is a parameter of shuffle sharding. Upon arrival of a request, a queue is chosen by randomly
// dealing a "hand" of this many queues and then picking one of minimum length.
HandSize int
// RequestWaitLimit is the maximum amount of time that a request may wait in a queue.
// If, by the end of that time, the request has not been dispatched then it is rejected.
RequestWaitLimit time.Duration
}
QueuingConfig defines the configuration of the queuing aspect of a QueueSet.
type Request ¶ added in v0.18.0
type Request interface {
// Finish determines whether to execute or reject the request and
// invokes `execute` if the decision is to execute the request.
// The returned `idle bool` value indicates whether the QueueSet
// was idle when the value was calculated, but might no longer be
// accurate by the time the client examines that value.
Finish(execute func()) (idle bool)
}
Request represents the remainder of the handling of one request
Source Files
Directories
¶
| Path | Synopsis |
|---|---|
|
Package queueset implements a technique called "fair queuing for server requests".
|
Package queueset implements a technique called "fair queuing for server requests". |