Alejandro Durante
56 lines
1.7 KiB
Go
56 lines
1.7 KiB
Go
package pond
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import (
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"runtime"
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)
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var maxProcs = runtime.GOMAXPROCS(0)
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// Preset pool resizing strategies
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var (
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// Eager maximizes responsiveness at the expense of higher resource usage,
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// which can reduce throughput under certain conditions.
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// This strategy is meant for worker pools that will operate at a small percentage of their capacity
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// most of the time and may occasionally receive bursts of tasks. It's the default strategy.
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Eager = func() ResizingStrategy { return RatedResizer(1) }
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// Balanced tries to find a balance between responsiveness and throughput.
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// It's suitable for general purpose worker pools or those
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// that will operate close to 50% of their capacity most of the time.
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Balanced = func() ResizingStrategy { return RatedResizer(maxProcs / 2) }
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// Lazy maximizes throughput at the expense of responsiveness.
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// This strategy is meant for worker pools that will operate close to their max. capacity most of the time.
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Lazy = func() ResizingStrategy { return RatedResizer(maxProcs) }
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)
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// ratedResizer implements a rated resizing strategy
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type ratedResizer struct {
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rate uint64
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hits uint64
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}
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// RatedResizer creates a resizing strategy which can be configured
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// to create workers at a specific rate when the pool has no idle workers.
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// rate: determines the number of tasks to receive before creating an extra worker.
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// A value of 3 can be interpreted as: "Create a new worker every 3 tasks".
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func RatedResizer(rate int) ResizingStrategy {
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if rate < 1 {
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rate = 1
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}
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return &ratedResizer{
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rate: uint64(rate),
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}
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}
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func (r *ratedResizer) Resize(runningWorkers, minWorkers, maxWorkers int) bool {
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if r.rate == 1 || runningWorkers == 0 {
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return true
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}
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r.hits++
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return r.hits%r.rate == 1
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}
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