261 lines
10 KiB
Go
261 lines
10 KiB
Go
// Copyright (C) 2018 spdf
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//
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// This file is part of Elektron.
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//
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// Elektron is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Elektron is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Elektron. If not, see <http://www.gnu.org/licenses/>.
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//
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package schedulers
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import (
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"fmt"
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"log"
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"time"
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mesos "github.com/mesos/mesos-go/api/v0/mesosproto"
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sched "github.com/mesos/mesos-go/api/v0/scheduler"
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"gitlab.com/spdf/elektron/def"
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elekLogDef "gitlab.com/spdf/elektron/logging/def"
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)
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type SchedPolicyContext interface {
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// Change the state of scheduling.
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SwitchSchedPol(s SchedPolicyState)
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}
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type SchedPolicyState interface {
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// Define the particular scheduling policy's methodology of resource offer consumption.
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ConsumeOffers(SchedPolicyContext, sched.SchedulerDriver, []*mesos.Offer)
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// Get information about the scheduling policy.
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GetInfo() (info struct {
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taskDist float64
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varCpuShare float64
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nextPolicyName string
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prevPolicyName string
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})
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// Update links to next and previous scheduling policy.
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UpdateLinks(info struct {
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nextPolicyName string
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prevPolicyName string
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})
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// Switch scheduling policy if necessary.
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SwitchIfNecessary(SchedPolicyContext)
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}
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type baseSchedPolicyState struct {
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SchedPolicyState
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// Keep track of the number of tasks that have been scheduled.
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numTasksScheduled int
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// Distribution of tasks that the scheduling policy is most appropriate for.
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// This distribution corresponds to the ratio of low power consuming tasks to
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// high power consuming tasks.
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TaskDistribution float64 `json:"taskDist"`
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// The average variance in cpu-share per task that this scheduling policy can cause.
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// Note: This number corresponds to a given workload.
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VarianceCpuSharePerTask float64 `json:"varCpuShare"`
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// Next and Previous scheduling policy in round-robin order.
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// This order is determined by the sorted order (non-decreasing or non-increasing) of taskDistribution.
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nextPolicyName string
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prevPolicyName string
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}
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// Scheduling policy switching criteria.
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// Takes a pointer to the BaseScheduler and returns the name of the scheduling policy to switch to.
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type switchBy func(*BaseScheduler) string
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var switchBasedOn map[string]switchBy = map[string]switchBy{
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"taskDist": switchTaskDistBased,
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"round-robin": switchRoundRobinBased,
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"rev-round-robin": switchRevRoundRobinBased,
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}
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func switchTaskDistBased(baseSchedRef *BaseScheduler) string {
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// Name of the scheduling policy to switch to.
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switchToPolicyName := ""
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// Record overhead to classify the tasks in the scheduling window and using the classification results
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// to determine the distribution of low power consuming and high power consuming tasks.
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startTime := time.Now()
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// Determine the distribution of tasks in the new scheduling window.
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taskDist, err := def.GetTaskDistributionInWindow(baseSchedRef.schedWindowSize, baseSchedRef.tasks)
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baseSchedRef.LogClsfnAndTaskDistOverhead(time.Now().Sub(startTime))
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baseSchedRef.Log(elekLogDef.GENERAL, fmt.Sprintf("Switching... TaskDistribution[%f]", taskDist))
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if err != nil {
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// All the tasks in the window were only classified into 1 cluster.
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// Max-Min and Max-GreedyMins would work the same way as Bin-Packing for this situation.
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// So, we have 2 choices to make. First-Fit or Bin-Packing.
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// If choose Bin-Packing, then there might be a performance degradation due to increase in
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// resource contention. So, First-Fit might be a better option to cater to the worst case
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// where all the tasks are power intensive tasks.
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// TODO: Another possibility is to do the exact opposite and choose Bin-Packing.
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// TODO[2]: Determine scheduling policy based on the distribution of tasks in the whole queue.
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switchToPolicyName = bp
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} else {
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// The tasks in the scheduling window were classified into 2 clusters, meaning that there is
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// some variety in the kind of tasks.
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// We now select the scheduling policy which is most appropriate for this distribution of tasks.
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first := schedPoliciesToSwitch[0]
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last := schedPoliciesToSwitch[len(schedPoliciesToSwitch)-1]
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if taskDist < first.sp.GetInfo().taskDist {
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switchToPolicyName = first.spName
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} else if taskDist > last.sp.GetInfo().taskDist {
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switchToPolicyName = last.spName
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} else {
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low := 0
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high := len(schedPoliciesToSwitch) - 1
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for low <= high {
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mid := (low + high) / 2
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if taskDist < schedPoliciesToSwitch[mid].sp.GetInfo().taskDist {
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high = mid - 1
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} else if taskDist > schedPoliciesToSwitch[mid].sp.GetInfo().taskDist {
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low = mid + 1
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} else {
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switchToPolicyName = schedPoliciesToSwitch[mid].spName
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break
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}
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}
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// We're here if low == high+1.
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// If haven't yet found the closest match.
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if switchToPolicyName == "" {
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lowDiff := schedPoliciesToSwitch[low].sp.GetInfo().taskDist - taskDist
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highDiff := taskDist - schedPoliciesToSwitch[high].sp.GetInfo().taskDist
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if lowDiff > highDiff {
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switchToPolicyName = schedPoliciesToSwitch[high].spName
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} else if highDiff > lowDiff {
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switchToPolicyName = schedPoliciesToSwitch[low].spName
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} else {
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// index doens't matter as the values at high and low are equidistant
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// from taskDist.
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switchToPolicyName = schedPoliciesToSwitch[high].spName
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}
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}
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}
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}
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return switchToPolicyName
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}
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// Switching based on a round-robin approach.
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// Not being considerate to the state of TaskQueue or the state of the cluster.
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func switchRoundRobinBased(baseSchedRef *BaseScheduler) string {
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// If haven't received any resource offers.
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if !baseSchedRef.hasReceivedResourceOffers {
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return schedPoliciesToSwitch[0].spName
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}
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return baseSchedRef.curSchedPolicy.GetInfo().nextPolicyName
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}
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// Switching based on a round-robin approach, but in the reverse order.
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// Not being considerate to the state of the TaskQueue or the state of the cluster.
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func switchRevRoundRobinBased(baseSchedRef *BaseScheduler) string {
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// If haven't received any resource offers.
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if !baseSchedRef.hasReceivedResourceOffers {
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return schedPoliciesToSwitch[len(schedPoliciesToSwitch)-1].spName
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}
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return baseSchedRef.curSchedPolicy.GetInfo().prevPolicyName
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}
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func (bsps *baseSchedPolicyState) SwitchIfNecessary(spc SchedPolicyContext) {
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baseSchedRef := spc.(*BaseScheduler)
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// Switching scheduling policy only if feature enabled from CLI.
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if baseSchedRef.schedPolSwitchEnabled {
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// Name of scheduling policy to switch to.
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switchToPolicyName := ""
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// Size of the new scheduling window.
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newSchedWindowSize := 0
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// If scheduling window has not been fixed, then determine the scheduling window based on the current
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// availability of resources on the cluster (Mesos perspective).
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if !baseSchedRef.toFixSchedWindow {
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// Need to compute the size of the scheduling window.
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// The next scheduling policy will schedule at max schedWindowSize number of tasks.
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newSchedWindowSize, baseSchedRef.numTasksInSchedWindow =
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baseSchedRef.schedWindowResStrategy.Apply(func() interface{} { return baseSchedRef.tasks })
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}
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// Now, we need to switch if the new scheduling window is > 0.
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if (!baseSchedRef.toFixSchedWindow && (newSchedWindowSize > 0)) ||
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(baseSchedRef.toFixSchedWindow && (baseSchedRef.schedWindowSize > 0)) {
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// If we haven't received any resource offers, then
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// check whether we need to fix the first scheduling policy to deploy.
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// If not, then determine the first scheduling policy based on the distribution of tasks
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// in the scheduling window.
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// Else,
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// Check whether the currently deployed scheduling policy has already scheduled the
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// schedWindowSize number of tasks.
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// If yes, then we switch to the scheduling policy based on the distribution of tasks in
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// the scheduling window.
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// If not, then we continue to use the currently deployed scheduling policy.
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if !baseSchedRef.hasReceivedResourceOffers {
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if baseSchedRef.nameOfFstSchedPolToDeploy != "" {
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switchToPolicyName = baseSchedRef.nameOfFstSchedPolToDeploy
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if !baseSchedRef.toFixSchedWindow {
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baseSchedRef.schedWindowSize = newSchedWindowSize
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}
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} else {
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// Decided to switch, so updating the window size.
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if !baseSchedRef.toFixSchedWindow {
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baseSchedRef.schedWindowSize = newSchedWindowSize
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}
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switchToPolicyName = switchBasedOn[baseSchedRef.schedPolSwitchCriteria](baseSchedRef)
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}
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} else {
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// Checking if the currently deployed scheduling policy has scheduled all the tasks in the window.
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if bsps.numTasksScheduled >= baseSchedRef.schedWindowSize {
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// Decided to switch, so updating the window size.
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if !baseSchedRef.toFixSchedWindow {
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baseSchedRef.schedWindowSize = newSchedWindowSize
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}
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switchToPolicyName = switchBasedOn[baseSchedRef.schedPolSwitchCriteria](baseSchedRef)
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} else {
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// We continue working with the currently deployed scheduling policy.
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log.Println("Continuing with the current scheduling policy...")
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log.Printf("TasksScheduled[%d], SchedWindowSize[%d]", bsps.numTasksScheduled,
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baseSchedRef.schedWindowSize)
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return
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}
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}
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// Switching scheduling policy.
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baseSchedRef.LogSchedPolicySwitch(switchToPolicyName, SchedPolicies[switchToPolicyName])
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baseSchedRef.SwitchSchedPol(SchedPolicies[switchToPolicyName])
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// Resetting the number of tasks scheduled as this is a new scheduling policy that has been
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// deployed.
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bsps.numTasksScheduled = 0
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} else {
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// We continue working with the currently deployed scheduling policy.
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log.Println("Continuing with the current scheduling policy...")
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log.Printf("TasksScheduled[%d], SchedWindowSize[%d]", bsps.numTasksScheduled,
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baseSchedRef.schedWindowSize)
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return
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}
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}
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}
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func (bsps *baseSchedPolicyState) GetInfo() (info struct {
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taskDist float64
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varCpuShare float64
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nextPolicyName string
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prevPolicyName string
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}) {
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info.taskDist = bsps.TaskDistribution
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info.varCpuShare = bsps.VarianceCpuSharePerTask
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info.nextPolicyName = bsps.nextPolicyName
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info.prevPolicyName = bsps.prevPolicyName
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return info
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}
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func (bsps *baseSchedPolicyState) UpdateLinks(info struct {
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nextPolicyName string
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prevPolicyName string
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}) {
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bsps.nextPolicyName = info.nextPolicyName
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bsps.prevPolicyName = info.prevPolicyName
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}
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