Official Go implementation of the Ethereum protocol
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 
go-ethereum/metrics/meter.go

189 lines
4.9 KiB

package metrics
import (
"math"
"sync"
"sync/atomic"
"time"
)
type MeterSnapshot interface {
Count() int64
Rate1() float64
Rate5() float64
Rate15() float64
RateMean() float64
}
// Meters count events to produce exponentially-weighted moving average rates
// at one-, five-, and fifteen-minutes and a mean rate.
type Meter interface {
Mark(int64)
Snapshot() MeterSnapshot
Stop()
}
// GetOrRegisterMeter returns an existing Meter or constructs and registers a
// new StandardMeter.
// Be sure to unregister the meter from the registry once it is of no use to
// allow for garbage collection.
func GetOrRegisterMeter(name string, r Registry) Meter {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, NewMeter).(Meter)
}
// NewMeter constructs a new StandardMeter and launches a goroutine.
// Be sure to call Stop() once the meter is of no use to allow for garbage collection.
func NewMeter() Meter {
if !Enabled {
return NilMeter{}
}
m := newStandardMeter()
arbiter.Lock()
defer arbiter.Unlock()
arbiter.meters[m] = struct{}{}
if !arbiter.started {
arbiter.started = true
go arbiter.tick()
}
return m
}
// NewInactiveMeter returns a meter but does not start any goroutines. This
// method is mainly intended for testing.
func NewInactiveMeter() Meter {
if !Enabled {
return NilMeter{}
}
m := newStandardMeter()
return m
}
// NewRegisteredMeter constructs and registers a new StandardMeter
// and launches a goroutine.
// Be sure to unregister the meter from the registry once it is of no use to
// allow for garbage collection.
func NewRegisteredMeter(name string, r Registry) Meter {
return GetOrRegisterMeter(name, r)
}
// meterSnapshot is a read-only copy of the meter's internal values.
type meterSnapshot struct {
count int64
rate1, rate5, rate15, rateMean float64
}
// Count returns the count of events at the time the snapshot was taken.
func (m *meterSnapshot) Count() int64 { return m.count }
// Rate1 returns the one-minute moving average rate of events per second at the
// time the snapshot was taken.
func (m *meterSnapshot) Rate1() float64 { return m.rate1 }
// Rate5 returns the five-minute moving average rate of events per second at
// the time the snapshot was taken.
func (m *meterSnapshot) Rate5() float64 { return m.rate5 }
// Rate15 returns the fifteen-minute moving average rate of events per second
// at the time the snapshot was taken.
func (m *meterSnapshot) Rate15() float64 { return m.rate15 }
// RateMean returns the meter's mean rate of events per second at the time the
// snapshot was taken.
func (m *meterSnapshot) RateMean() float64 { return m.rateMean }
// NilMeter is a no-op Meter.
type NilMeter struct{}
func (NilMeter) Count() int64 { return 0 }
func (NilMeter) Mark(n int64) {}
func (NilMeter) Snapshot() MeterSnapshot { return (*emptySnapshot)(nil) }
func (NilMeter) Stop() {}
// StandardMeter is the standard implementation of a Meter.
type StandardMeter struct {
count atomic.Int64
uncounted atomic.Int64 // not yet added to the EWMAs
rateMean atomic.Uint64
a1, a5, a15 EWMA
startTime time.Time
stopped atomic.Bool
}
func newStandardMeter() *StandardMeter {
return &StandardMeter{
a1: NewEWMA1(),
a5: NewEWMA5(),
a15: NewEWMA15(),
startTime: time.Now(),
}
}
// Stop stops the meter, Mark() will be a no-op if you use it after being stopped.
func (m *StandardMeter) Stop() {
if stopped := m.stopped.Swap(true); !stopped {
arbiter.Lock()
delete(arbiter.meters, m)
arbiter.Unlock()
}
}
// Mark records the occurrence of n events.
func (m *StandardMeter) Mark(n int64) {
m.uncounted.Add(n)
}
// Snapshot returns a read-only copy of the meter.
func (m *StandardMeter) Snapshot() MeterSnapshot {
return &meterSnapshot{
count: m.count.Load() + m.uncounted.Load(),
rate1: m.a1.Snapshot().Rate(),
rate5: m.a5.Snapshot().Rate(),
rate15: m.a15.Snapshot().Rate(),
rateMean: math.Float64frombits(m.rateMean.Load()),
}
}
func (m *StandardMeter) tick() {
// Take the uncounted values, add to count
n := m.uncounted.Swap(0)
count := m.count.Add(n)
m.rateMean.Store(math.Float64bits(float64(count) / time.Since(m.startTime).Seconds()))
// Update the EWMA's internal state
m.a1.Update(n)
m.a5.Update(n)
m.a15.Update(n)
// And trigger them to calculate the rates
m.a1.Tick()
m.a5.Tick()
m.a15.Tick()
}
// meterArbiter ticks meters every 5s from a single goroutine.
// meters are references in a set for future stopping.
type meterArbiter struct {
sync.RWMutex
started bool
meters map[*StandardMeter]struct{}
ticker *time.Ticker
}
var arbiter = meterArbiter{ticker: time.NewTicker(5 * time.Second), meters: make(map[*StandardMeter]struct{})}
// Ticks meters on the scheduled interval
func (ma *meterArbiter) tick() {
for range ma.ticker.C {
ma.tickMeters()
}
}
func (ma *meterArbiter) tickMeters() {
ma.RLock()
defer ma.RUnlock()
for meter := range ma.meters {
meter.tick()
}
}