requested_to_capacity_ratio.go

Documentation: k8s.io/kubernetes/pkg/scheduler/framework/plugins/noderesources

     1  /*
     2  Copyright 2019 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package noderesources
    18  
    19  import (
    20  	"math"
    21  
    22  	"k8s.io/kubernetes/pkg/scheduler/apis/config"
    23  	"k8s.io/kubernetes/pkg/scheduler/framework"
    24  	"k8s.io/kubernetes/pkg/scheduler/framework/plugins/helper"
    25  )
    26  
    27  const maxUtilization = 100
    28  
    29  // buildRequestedToCapacityRatioScorerFunction allows users to apply bin packing
    30  // on core resources like CPU, Memory as well as extended resources like accelerators.
    31  func buildRequestedToCapacityRatioScorerFunction(scoringFunctionShape helper.FunctionShape, resources []config.ResourceSpec) func([]int64, []int64) int64 {
    32  	rawScoringFunction := helper.BuildBrokenLinearFunction(scoringFunctionShape)
    33  	resourceScoringFunction := func(requested, capacity int64) int64 {
    34  		if capacity == 0 || requested > capacity {
    35  			return rawScoringFunction(maxUtilization)
    36  		}
    37  
    38  		return rawScoringFunction(requested * maxUtilization / capacity)
    39  	}
    40  	return func(requested, allocable []int64) int64 {
    41  		var nodeScore, weightSum int64
    42  		for i := range requested {
    43  			if allocable[i] == 0 {
    44  				continue
    45  			}
    46  			weight := resources[i].Weight
    47  			resourceScore := resourceScoringFunction(requested[i], allocable[i])
    48  			if resourceScore > 0 {
    49  				nodeScore += resourceScore * weight
    50  				weightSum += weight
    51  			}
    52  		}
    53  		if weightSum == 0 {
    54  			return 0
    55  		}
    56  		return int64(math.Round(float64(nodeScore) / float64(weightSum)))
    57  	}
    58  }
    59  
    60  func requestedToCapacityRatioScorer(resources []config.ResourceSpec, shape []config.UtilizationShapePoint) func([]int64, []int64) int64 {
    61  	shapes := make([]helper.FunctionShapePoint, 0, len(shape))
    62  	for _, point := range shape {
    63  		shapes = append(shapes, helper.FunctionShapePoint{
    64  			Utilization: int64(point.Utilization),
    65  			// MaxCustomPriorityScore may diverge from the max score used in the scheduler and defined by MaxNodeScore,
    66  			// therefore we need to scale the score returned by requested to capacity ratio to the score range
    67  			// used by the scheduler.
    68  			Score: int64(point.Score) * (framework.MaxNodeScore / config.MaxCustomPriorityScore),
    69  		})
    70  	}
    71  
    72  	return buildRequestedToCapacityRatioScorerFunction(shapes, resources)
    73  }
    74
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