| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package pinger |
| 4 | |
| 5 | import ( |
| 6 | "sync" |
| 7 | "time" |
| 8 | ) |
| 9 | |
| 10 | type hostState struct { |
| 11 | ewma float64 |
| 12 | sma []float64 |
| 13 | } |
| 14 | |
| 15 | type stateStore struct { |
| 16 | mu sync.Mutex |
| 17 | byHost map[string]*hostState |
| 18 | } |
| 19 | |
| 20 | func newStateStore() *stateStore { |
| 21 | return &stateStore{ |
| 22 | byHost: make(map[string]*hostState), |
| 23 | } |
| 24 | } |
| 25 | |
| 26 | func (s *stateStore) update(host string, current time.Duration, cfg AnalysisConfig) (time.Duration, time.Duration) { |
| 27 | s.mu.Lock() |
| 28 | defer s.mu.Unlock() |
| 29 | |
| 30 | st, ok := s.byHost[host] |
| 31 | if !ok { |
| 32 | st = &hostState{} |
| 33 | s.byHost[host] = st |
| 34 | } |
| 35 | |
| 36 | curr := float64(current) |
| 37 | alpha := 1.0 / float64(cfg.JitterEWMASamples) |
| 38 | st.ewma = alpha*curr + (1-alpha)*st.ewma |
| 39 | |
| 40 | st.sma = append(st.sma, curr) |
| 41 | if len(st.sma) > cfg.JitterSMAWindow { |
| 42 | st.sma = st.sma[1:] |
| 43 | } |
| 44 | |
| 45 | var sum float64 |
| 46 | for _, v := range st.sma { |
| 47 | sum += v |
| 48 | } |
| 49 | |
| 50 | return time.Duration(st.ewma), time.Duration(sum / float64(len(st.sma))) |
| 51 | } |