package hudson.model.queue;
import com.google.common.collect.Iterables;
import hudson.Extension;
import hudson.model.Computer;
import hudson.model.Executor;
import jenkins.model.Jenkins;
import hudson.model.InvisibleAction;
import hudson.model.Queue.BuildableItem;
import hudson.model.queue.MappingWorksheet.ExecutorChunk;
import hudson.model.queue.MappingWorksheet.ExecutorSlot;
import hudson.model.queue.MappingWorksheet.Mapping;
import hudson.model.queue.MappingWorksheet.WorkChunk;
import hudson.util.TimeUnit2;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
/**
* Experimental.
*
* @author Kohsuke Kawaguchi
*/
public class BackFiller extends LoadPredictor {
private boolean recursion = false;
@Override
public Iterable<FutureLoad> predict(MappingWorksheet plan, Computer computer, long start, long end) {
TimeRange timeRange = new TimeRange(start, end - start);
List<FutureLoad> loads = new ArrayList<FutureLoad>();
for (BuildableItem bi : Jenkins.getInstance().getQueue().getBuildableItems()) {
TentativePlan tp = bi.getAction(TentativePlan.class);
if (tp==null) {// do this even for bi==plan.item ensures that we have FIFO semantics in tentative plans.
tp = makeTentativePlan(bi);
if (tp==null) continue; // no viable plan.
}
if (tp.isStale()) {
// if the tentative plan is stale, just keep on pushing it to the current time
// (if we recreate the plan, it'll be put at the end of the queue, whereas this job
// should actually get priority over others)
tp.range.shiftTo(System.currentTimeMillis());
}
// don't let its own tentative plan count when considering a scheduling for a job
if (plan.item==bi) continue;
// no overlap in the time span, meaning this plan is for a distant future
if (!timeRange.overlapsWith(tp.range)) continue;
// if this tentative plan has no baring on this computer, that's ignorable
Integer i = tp.footprint.get(computer);
if (i==null) continue;
return Collections.singleton(tp.range.toFutureLoad(i));
}
return loads;
}
private static final class PseudoExecutorSlot extends ExecutorSlot {
private Executor executor;
private PseudoExecutorSlot(Executor executor) {
this.executor = executor;
}
@Override
public Executor getExecutor() {
return executor;
}
@Override
public boolean isAvailable() {
return true;
}
// this slot isn't executable
@Override
protected void set(WorkUnit p) {
throw new UnsupportedOperationException();
}
}
private TentativePlan makeTentativePlan(BuildableItem bi) {
if (recursion) return null;
recursion = true;
try {
// pretend for now that all executors are available and decide some assignment that's executable.
List<PseudoExecutorSlot> slots = new ArrayList<PseudoExecutorSlot>();
for (Computer c : Jenkins.getInstance().getComputers()) {
if (c.isOffline()) continue;
for (Executor e : c.getExecutors()) {
slots.add(new PseudoExecutorSlot(e));
}
}
// also ignore all load predictions as we just want to figure out some executable assignment
// and we are not trying to figure out if this task is executable right now.
MappingWorksheet worksheet = new MappingWorksheet(bi, slots, Collections.<LoadPredictor>emptyList());
Mapping m = Jenkins.getInstance().getQueue().getLoadBalancer().map(bi.task, worksheet);
if (m==null) return null;
// figure out how many executors we need on each computer?
Map<Computer,Integer> footprint = new HashMap<Computer, Integer>();
for (Entry<WorkChunk, ExecutorChunk> e : m.toMap().entrySet()) {
Computer c = e.getValue().computer;
Integer v = footprint.get(c);
if (v==null) v = 0;
v += e.getKey().size();
footprint.put(c,v);
}
// the point of a tentative plan is to displace other jobs to create a point in time
// where this task can start executing. An incorrectly estimated duration is not
// a problem in this regard, as we just need enough idle executors in the right moment.
// The downside of guessing the duration wrong is that we can end up creating tentative plans
// afterward that may be incorrect, but those plans will be rebuilt.
long d = bi.task.getEstimatedDuration();
if (d<=0) d = TimeUnit2.MINUTES.toMillis(5);
TimeRange slot = new TimeRange(System.currentTimeMillis(), d);
// now, based on the real predicted loads, figure out the approximation of when we can
// start executing this guy.
for (Entry<Computer, Integer> e : footprint.entrySet()) {
Computer computer = e.getKey();
Timeline timeline = new Timeline();
for (LoadPredictor lp : LoadPredictor.all()) {
for (FutureLoad fl : Iterables.limit(lp.predict(worksheet, computer, slot.start, slot.end),100)) {
timeline.insert(fl.startTime, fl.startTime+fl.duration, fl.numExecutors);
}
}
Long x = timeline.fit(slot.start, slot.duration, computer.countExecutors()-e.getValue());
// if no suitable range was found in [slot.start,slot.end), slot.end would be a good approximation
if (x==null) x = slot.end;
slot = slot.shiftTo(x);
}
TentativePlan tp = new TentativePlan(footprint, slot);
bi.addAction(tp);
return tp;
} finally {
recursion = false;
}
}
/**
* Represents a duration in time.
*/
private static final class TimeRange {
public final long start;
public final long duration;
public final long end;
private TimeRange(long start, long duration) {
this.start = start;
this.duration = duration;
this.end = start+duration;
}
public boolean overlapsWith(TimeRange that) {
return (this.start <= that.start && that.start <=this.end)
|| (that.start <= this.start && this.start <=that.end);
}
public FutureLoad toFutureLoad(int size) {
return new FutureLoad(start,duration,size);
}
public TimeRange shiftTo(long newStart) {
if (newStart==start) return this;
return new TimeRange(newStart,duration);
}
}
public static final class TentativePlan extends InvisibleAction {
private final Map<Computer,Integer> footprint;
public final TimeRange range;
public TentativePlan(Map<Computer, Integer> footprint, TimeRange range) {
this.footprint = footprint;
this.range = range;
}
public Object writeReplace() {// don't persist
return null;
}
public boolean isStale() {
return range.end < System.currentTimeMillis();
}
}
/**
* Once this feature stabilizes, move it to the heavyjob plugin
*/
@Extension
public static BackFiller newInstance() {
if (Boolean.getBoolean(BackFiller.class.getName()))
return new BackFiller();
return null;
}
}