mirror of
https://github.com/prometheus/prometheus.git
synced 2024-11-16 10:34:06 -08:00
69 lines
1.7 KiB
Go
69 lines
1.7 KiB
Go
// Copyright 2013 The Prometheus Authors
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package remote
|
|
|
|
import (
|
|
"sync"
|
|
"sync/atomic"
|
|
"time"
|
|
)
|
|
|
|
// ewmaRate tracks an exponentially weighted moving average of a per-second rate.
|
|
type ewmaRate struct {
|
|
newEvents int64
|
|
alpha float64
|
|
interval time.Duration
|
|
lastRate float64
|
|
init bool
|
|
mutex sync.Mutex
|
|
}
|
|
|
|
// newEWMARate always allocates a new ewmaRate, as this guarantees the atomically
|
|
// accessed int64 will be aligned on ARM. See prometheus#2666.
|
|
func newEWMARate(alpha float64, interval time.Duration) *ewmaRate {
|
|
return &ewmaRate{
|
|
alpha: alpha,
|
|
interval: interval,
|
|
}
|
|
}
|
|
|
|
// rate returns the per-second rate.
|
|
func (r *ewmaRate) rate() float64 {
|
|
r.mutex.Lock()
|
|
defer r.mutex.Unlock()
|
|
return r.lastRate
|
|
}
|
|
|
|
// tick assumes to be called every r.interval.
|
|
func (r *ewmaRate) tick() {
|
|
newEvents := atomic.LoadInt64(&r.newEvents)
|
|
atomic.AddInt64(&r.newEvents, -newEvents)
|
|
instantRate := float64(newEvents) / r.interval.Seconds()
|
|
|
|
r.mutex.Lock()
|
|
defer r.mutex.Unlock()
|
|
|
|
if r.init {
|
|
r.lastRate += r.alpha * (instantRate - r.lastRate)
|
|
} else {
|
|
r.init = true
|
|
r.lastRate = instantRate
|
|
}
|
|
}
|
|
|
|
// inc counts one event.
|
|
func (r *ewmaRate) incr(incr int64) {
|
|
atomic.AddInt64(&r.newEvents, incr)
|
|
}
|