go.uber.org/cadence@v1.2.9/internal/common/autoscaler/recommender.go (about)

     1  // Copyright (c) 2017-2021 Uber Technologies Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
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     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package autoscaler
    22  
    23  import "math"
    24  
    25  // Recommender a recommendation generator for ResourceUnit
    26  type Recommender interface {
    27  	Recommend(currentResource ResourceUnit, currentUsages Usages) ResourceUnit
    28  }
    29  
    30  type linearRecommender struct {
    31  	lower, upper ResourceUnit
    32  	targetUsages Usages
    33  }
    34  
    35  // NewLinearRecommender create a linear Recommender
    36  func NewLinearRecommender(lower, upper ResourceUnit, targetUsages Usages) Recommender {
    37  	return &linearRecommender{
    38  		lower:        lower,
    39  		upper:        upper,
    40  		targetUsages: targetUsages,
    41  	}
    42  }
    43  
    44  // Recommend recommends the new value
    45  func (l *linearRecommender) Recommend(currentResource ResourceUnit, currentUsages Usages) ResourceUnit {
    46  	var recommend float64
    47  
    48  	// average recommendation over all UsageType
    49  	for usageType := range currentUsages {
    50  		var r float64
    51  		if l.targetUsages[usageType] == 0 { // avoid division by zero
    52  			r = math.MaxFloat64
    53  		} else {
    54  			if currentUsages[usageType].Value() == float64(1000) {
    55  				r = l.upper.Value()
    56  			} else {
    57  				r = currentResource.Value() * currentUsages[usageType].Value() / l.targetUsages[usageType].Value()
    58  			}
    59  		}
    60  		// boundary check
    61  		r = math.Min(l.upper.Value(), math.Max(l.lower.Value(), r))
    62  		recommend += r
    63  	}
    64  	recommend /= float64(len(currentUsages))
    65  	return ResourceUnit(recommend)
    66  }