93 lines
2.3 KiB
Go
93 lines
2.3 KiB
Go
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// Licensed to Elasticsearch B.V. under one or more contributor
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// license agreements. See the NOTICE file distributed with
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// this work for additional information regarding copyright
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// ownership. Elasticsearch B.V. licenses this file to you under
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// the Apache License, Version 2.0 (the "License"); you may
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// 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,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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package logstash
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import (
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"math"
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"sync/atomic"
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)
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type window struct {
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windowSize int32
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maxOkWindowSize int // max window size sending was successful for
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maxWindowSize int
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}
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func newWindower(start, max int) *window {
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w := &window{}
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w.init(start, max)
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return w
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}
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func (w *window) init(start, max int) {
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*w = window{
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windowSize: int32(start),
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maxWindowSize: max,
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}
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}
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func (w *window) get() int {
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return int(atomic.LoadInt32(&w.windowSize))
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}
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// Increase window size by factor 1.5 until max window size
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// (window size grows exponentially)
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// TODO: use duration until ACK to estimate an ok max window size value
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func (w *window) tryGrowWindow(batchSize int) {
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windowSize := w.get()
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if windowSize <= batchSize {
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if w.maxOkWindowSize < windowSize {
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w.maxOkWindowSize = windowSize
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newWindowSize := int(math.Ceil(1.5 * float64(windowSize)))
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if windowSize <= batchSize && batchSize < newWindowSize {
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newWindowSize = batchSize
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}
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if newWindowSize > w.maxWindowSize {
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newWindowSize = int(w.maxWindowSize)
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}
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windowSize = newWindowSize
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} else if windowSize < w.maxOkWindowSize {
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windowSize = int(math.Ceil(1.5 * float64(windowSize)))
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if windowSize > w.maxOkWindowSize {
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windowSize = w.maxOkWindowSize
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}
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}
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atomic.StoreInt32(&w.windowSize, int32(windowSize))
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}
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}
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func (w *window) shrinkWindow() {
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windowSize := w.get()
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orig := windowSize
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windowSize = windowSize / 2
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if windowSize < minWindowSize {
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windowSize = minWindowSize
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if windowSize == orig {
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return
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}
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}
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atomic.StoreInt32(&w.windowSize, int32(windowSize))
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}
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