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https://github.com/status-im/go-watchdog.git
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4558d98653
This commit introduces a major rewrite of go-watchdog. * HeapDriven and SystemDriven are now distinct run modes. * WIP ProcessDriven that uses cgroups. * Policies are now stateless, pure and greatly simplified. * Policies now return the next utilization at which GC should run. The watchdog enforces that value differently depending on the run mode. * The heap-driven run mode adjusts GOGC dynamically. This places the responsibility on the Go runtime to honour the trigger point, and results in more robust logic that is not vulnerable to very quick bursts within sampling periods. * The heap-driven run mode is no longer polling (interval-driven). Instead, it relies entirely on GC signals. * The Silence and Emergency features of the watermark policy have been removed. If utilization is above the last watermark, the policy will request immediate GC. * Races removed.
42 lines
1.3 KiB
Go
42 lines
1.3 KiB
Go
package watchdog
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// NewWatermarkPolicy creates a watchdog policy that schedules GC at concrete
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// watermarks. When queried, it will determine the next trigger point based
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// on the current utilisation. If the last watermark is surpassed,
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// the policy will request immediate GC.
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func NewWatermarkPolicy(watermarks ...float64) PolicyCtor {
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return func(limit uint64) (Policy, error) {
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p := new(watermarkPolicy)
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p.limit = limit
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p.thresholds = make([]uint64, 0, len(watermarks))
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for _, m := range watermarks {
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p.thresholds = append(p.thresholds, uint64(float64(limit)*m))
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}
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Logger.Infof("initialized watermark watchdog policy; watermarks: %v; thresholds: %v", p.watermarks, p.thresholds)
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return p, nil
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}
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}
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type watermarkPolicy struct {
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// watermarks are the percentual amounts of limit.
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watermarks []float64
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// thresholds are the absolute trigger points of this policy.
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thresholds []uint64
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limit uint64
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}
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var _ Policy = (*watermarkPolicy)(nil)
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func (w *watermarkPolicy) Evaluate(_ UtilizationType, used uint64) (next uint64, immediate bool) {
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Logger.Debugf("watermark policy: evaluating; utilization: %d/%d (used/limit)", used, w.limit)
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var i int
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for ; i < len(w.thresholds); i++ {
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t := w.thresholds[i]
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if used < t {
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return t, false
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}
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}
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// we reached the maximum threshold, so fire immediately.
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return used, true
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}
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