mirror of
https://github.com/k3s-io/k3s.git
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75 lines
1.9 KiB
Go
75 lines
1.9 KiB
Go
// Copyright 2015 Google Inc. All Rights Reserved.
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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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package summary
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import (
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info "github.com/google/cadvisor/info/v2"
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)
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// Manages a buffer of usage samples.
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// This is similar to stats buffer in cache/memory.
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// The main difference is that we do not pre-allocate the buffer as most containers
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// won't live that long.
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type SamplesBuffer struct {
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// list of collected samples.
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samples []info.Usage
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// maximum size this buffer can grow to.
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maxSize int
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// index for the latest sample.
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index int
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}
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// Initializes an empty buffer.
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func NewSamplesBuffer(size int) *SamplesBuffer {
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return &SamplesBuffer{
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index: -1,
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maxSize: size,
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}
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}
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// Returns the current number of samples in the buffer.
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func (s *SamplesBuffer) Size() int {
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return len(s.samples)
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}
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// Add an element to the buffer. Oldest one is overwritten if required.
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func (s *SamplesBuffer) Add(stat info.Usage) {
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if len(s.samples) < s.maxSize {
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s.samples = append(s.samples, stat)
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s.index++
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return
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}
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s.index = (s.index + 1) % s.maxSize
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s.samples[s.index] = stat
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}
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// Returns pointers to the last 'n' stats.
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func (s *SamplesBuffer) RecentStats(n int) []*info.Usage {
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if n > len(s.samples) {
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n = len(s.samples)
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}
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start := s.index - (n - 1)
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if start < 0 {
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start += len(s.samples)
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}
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out := make([]*info.Usage, n)
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for i := 0; i < n; i++ {
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index := (start + i) % len(s.samples)
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out[i] = &s.samples[index]
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}
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return out
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}
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