mirror of
https://github.com/minio/minio.git
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121 lines
3.5 KiB
Go
121 lines
3.5 KiB
Go
/*
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* Minio Cloud Storage, (C) 2017 Minio, Inc.
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*
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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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*/
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package cmd
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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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const (
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dynamicTimeoutIncreaseThresholdPct = 0.33 // Upper threshold for failures in order to increase timeout
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dynamicTimeoutDecreaseThresholdPct = 0.10 // Lower threshold for failures in order to decrease timeout
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dynamicTimeoutLogSize = 16
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maxDuration = time.Duration(1<<63 - 1)
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)
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// timeouts that are dynamically adapted based on actual usage results
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type dynamicTimeout struct {
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timeout int64
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minimum int64
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entries int64
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log [dynamicTimeoutLogSize]time.Duration
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mutex sync.Mutex
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}
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// newDynamicTimeout returns a new dynamic timeout initialized with timeout value
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func newDynamicTimeout(timeout, minimum time.Duration) *dynamicTimeout {
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return &dynamicTimeout{timeout: int64(timeout), minimum: int64(minimum)}
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}
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// Timeout returns the current timeout value
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func (dt *dynamicTimeout) Timeout() time.Duration {
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return time.Duration(atomic.LoadInt64(&dt.timeout))
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}
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// LogSuccess logs the duration of a successful action that
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// did not hit the timeout
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func (dt *dynamicTimeout) LogSuccess(duration time.Duration) {
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dt.logEntry(duration)
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}
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// LogFailure logs an action that hit the timeout
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func (dt *dynamicTimeout) LogFailure() {
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dt.logEntry(maxDuration)
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}
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// logEntry stores a log entry
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func (dt *dynamicTimeout) logEntry(duration time.Duration) {
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entries := int(atomic.AddInt64(&dt.entries, 1))
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index := entries - 1
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if index < dynamicTimeoutLogSize {
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dt.mutex.Lock()
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dt.log[index] = duration
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dt.mutex.Unlock()
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}
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if entries == dynamicTimeoutLogSize {
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dt.mutex.Lock()
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// Make copy on stack in order to call adjust()
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logCopy := [dynamicTimeoutLogSize]time.Duration{}
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copy(logCopy[:], dt.log[:])
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// reset log entries
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atomic.StoreInt64(&dt.entries, 0)
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dt.mutex.Unlock()
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dt.adjust(logCopy)
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}
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}
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// adjust changes the value of the dynamic timeout based on the
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// previous results
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func (dt *dynamicTimeout) adjust(entries [dynamicTimeoutLogSize]time.Duration) {
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failures, average := 0, 0
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for i := 0; i < len(entries); i++ {
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if entries[i] == maxDuration {
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failures++
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} else {
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average += int(entries[i])
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}
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}
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if failures < len(entries) {
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average /= len(entries) - failures
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}
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timeOutHitPct := float64(failures) / float64(len(entries))
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if timeOutHitPct > dynamicTimeoutIncreaseThresholdPct {
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// We are hitting the timeout too often, so increase the timeout by 25%
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timeout := atomic.LoadInt64(&dt.timeout) * 125 / 100
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atomic.StoreInt64(&dt.timeout, timeout)
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} else if timeOutHitPct < dynamicTimeoutDecreaseThresholdPct {
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// We are hitting the timeout relatively few times, so decrease the timeout
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average = average * 125 / 100 // Add buffer of 25% on top of average
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timeout := (atomic.LoadInt64(&dt.timeout) + int64(average)) / 2 // Middle between current timeout and average success
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if timeout < dt.minimum {
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timeout = dt.minimum
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}
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atomic.StoreInt64(&dt.timeout, timeout)
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}
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}
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