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elektron/utilities/schedUtils/schedUtils.go
2018-10-06 20:03:14 -07:00

118 lines
4.1 KiB
Go

// Copyright (C) 2018 spdf
//
// This file is part of Elektron.
//
// Elektron is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Elektron is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Elektron. If not, see <http://www.gnu.org/licenses/>.
//
package schedUtils
import (
"log"
"gitlab.com/spdf/elektron/def"
"gitlab.com/spdf/elektron/utilities"
)
// Criteria for resizing the scheduling window.
type SchedulingWindowResizingCriteria string
var SchedWindowResizingCritToStrategy = map[SchedulingWindowResizingCriteria]SchedWindowResizingStrategy{
"fillNextOfferCycle": &fillNextOfferCycle{},
}
// Interface for a scheduling window resizing strategy.
type SchedWindowResizingStrategy interface {
// Apply the window resizing strategy and return the size of the scheduling window and the number tasks that
// were traversed in the process.
// The size of the scheduling window would correspond to the total number of
// instances (flattened) that can be scheduled in the next offer cycle.
// The number of tasks would correspond to number of different tasks (instances not included).
Apply(func() interface{}) (int, int)
}
// Scheduling window resizing strategy that attempts to resize the scheduling window
// to include as many tasks as possible so as to make the most use of the next offer cycle.
type fillNextOfferCycle struct{}
func (s *fillNextOfferCycle) Apply(getArgs func() interface{}) (int, int) {
return s.apply(getArgs().([]def.Task))
}
// Loop over the unscheduled tasks, in submission order, and determine the maximum
// number of tasks that can be scheduled in the next offer cycle.
// As the offers get smaller and smaller, this approach might lead to an increase in internal fragmentation.
//
// Note: To be able to make the most use of the next offer cycle, one would need to perform a non-polynomial search
// which is computationally expensive.
func (s *fillNextOfferCycle) apply(taskQueue []def.Task) (int, int) {
clusterwideResourceCount := utilities.GetClusterwideResourceAvailability()
newSchedWindow := 0
filledCPU := 0.0
filledRAM := 0.0
// Can we schedule another task.
canSchedule := func(t def.Task) bool {
if ((filledCPU + t.CPU) <= clusterwideResourceCount.UnusedCPU) &&
((filledRAM + t.RAM) <= clusterwideResourceCount.UnusedRAM) {
return true
}
return false
}
done := false
// Track of number of tasks traversed.
numberOfTasksTraversed := 0
for _, task := range taskQueue {
numberOfTasksTraversed++
for i := *task.Instances; i > 0; i-- {
log.Printf("Checking if Instance #%d of Task[%s] can be scheduled "+
"during the next offer cycle...", i, task.Name)
if canSchedule(task) {
filledCPU += task.CPU
filledRAM += task.RAM
newSchedWindow++
} else {
done = true
if i == *task.Instances {
// We don't count this task if none of the instances could be scheduled.
numberOfTasksTraversed--
}
break
}
}
if done {
break
}
}
// Hacking...
// 2^window is window<=7
// if newSchedWindow <= 7 {
// newSchedWindow = int(math.Pow(2.0, float64(newSchedWindow)))
// }
// Another hack. Getting rid of window to see whether the idle power consumption can be amortized.
// Setting window as the length of the entire queue.
// Also setting numberOfTasksTraversed to the number of tasks in the entire queue.
// TODO: Create another resizing strategy that sizes the window to the length of the entire pending queue.
// flattenedLength := 0
// numTasks := 0
// for _, ts := range taskQueue {
// numTasks++
// flattenedLength += *ts.Instances
// }
// newSchedWindow = flattenedLength
// numberOfTasksTraversed = numTasks
return newSchedWindow, numberOfTasksTraversed
}