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a6a55c433c
The desired shards calculation now properly keeps track of the rate of pending samples, and uses the previously unused integralAccumulator to adjust for missing information in the desired shards calculation. Also, configure more capacity for each shard. The default 10 capacity causes shards to block on each other while sending remote requests. Default to a 500 sample capacity and explain in the documentation that having more capacity will help throughput. Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
68 lines
1.7 KiB
Go
68 lines
1.7 KiB
Go
// Copyright 2013 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package remote
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import (
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"sync"
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"sync/atomic"
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"time"
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)
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// ewmaRate tracks an exponentially weighted moving average of a per-second rate.
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type ewmaRate struct {
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newEvents int64
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alpha float64
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interval time.Duration
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lastRate float64
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init bool
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mutex sync.Mutex
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}
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// newEWMARate always allocates a new ewmaRate, as this guarantees the atomically
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// accessed int64 will be aligned on ARM. See prometheus#2666.
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func newEWMARate(alpha float64, interval time.Duration) *ewmaRate {
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return &ewmaRate{
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alpha: alpha,
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interval: interval,
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}
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}
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// rate returns the per-second rate.
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func (r *ewmaRate) rate() float64 {
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r.mutex.Lock()
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defer r.mutex.Unlock()
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return r.lastRate
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}
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// tick assumes to be called every r.interval.
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func (r *ewmaRate) tick() {
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newEvents := atomic.SwapInt64(&r.newEvents, 0)
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instantRate := float64(newEvents) / r.interval.Seconds()
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r.mutex.Lock()
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defer r.mutex.Unlock()
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if r.init {
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r.lastRate += r.alpha * (instantRate - r.lastRate)
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} else if newEvents > 0 {
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r.init = true
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r.lastRate = instantRate
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}
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}
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// inc counts one event.
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func (r *ewmaRate) incr(incr int64) {
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atomic.AddInt64(&r.newEvents, incr)
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}
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