1 //go:build linux 2 // +build linux 3 4 /* 5 Copyright 2018 The Kubernetes Authors. 6 7 Licensed under the Apache License, Version 2.0 (the "License"); 8 you may not use this file except in compliance with the License. 9 You may obtain a copy of the License at 10 11 http://www.apache.org/licenses/LICENSE-2.0 12 13 Unless required by applicable law or agreed to in writing, software 14 distributed under the License is distributed on an "AS IS" BASIS, 15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 See the License for the specific language governing permissions and 17 limitations under the License. 18 */ 19 20 package kuberuntime 21 22 import ( 23 "k8s.io/kubernetes/pkg/kubelet/cm" 24 "math" 25 ) 26 27 const ( 28 milliCPUToCPU = 1000 29 30 // 100000 microseconds is equivalent to 100ms 31 quotaPeriod = 100000 32 // 1000 microseconds is equivalent to 1ms 33 // defined here: 34 // https://github.com/torvalds/linux/blob/cac03ac368fabff0122853de2422d4e17a32de08/kernel/sched/core.c#L10546 35 minQuotaPeriod = 1000 36 ) 37 38 // milliCPUToQuota converts milliCPU to CFS quota and period values 39 // Input parameters and resulting value is number of microseconds. 40 func milliCPUToQuota(milliCPU int64, period int64) (quota int64) { 41 // CFS quota is measured in two values: 42 // - cfs_period_us=100ms (the amount of time to measure usage across) 43 // - cfs_quota=20ms (the amount of cpu time allowed to be used across a period) 44 // so in the above example, you are limited to 20% of a single CPU 45 // for multi-cpu environments, you just scale equivalent amounts 46 // see https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt for details 47 if milliCPU == 0 { 48 return 49 } 50 51 // we then convert your milliCPU to a value normalized over a period 52 quota = (milliCPU * period) / milliCPUToCPU 53 54 // quota needs to be a minimum of 1ms. 55 if quota < minQuotaPeriod { 56 quota = minQuotaPeriod 57 } 58 59 return 60 } 61 62 // sharesToMilliCPU converts CpuShares (cpu.shares) to milli-CPU value 63 // TODO(vinaykul,InPlacePodVerticalScaling): Address issue that sets min req/limit to 2m/10m before beta 64 // See: https://github.com/kubernetes/kubernetes/pull/102884#discussion_r662552642 65 func sharesToMilliCPU(shares int64) int64 { 66 milliCPU := int64(0) 67 if shares >= int64(cm.MinShares) { 68 milliCPU = int64(math.Ceil(float64(shares*milliCPUToCPU) / float64(cm.SharesPerCPU))) 69 } 70 return milliCPU 71 } 72 73 // quotaToMilliCPU converts cpu.cfs_quota_us and cpu.cfs_period_us to milli-CPU value 74 func quotaToMilliCPU(quota int64, period int64) int64 { 75 if quota == -1 { 76 return int64(0) 77 } 78 return (quota * milliCPUToCPU) / period 79 } 80