X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/0eb72b526bf8bbb011551ecf019f604e17a534f1..7499f61a2912cfdb1a316808fafa6e6ee77ee2e0:/services/crunch-dispatch-slurm/squeue.go

diff --git a/services/crunch-dispatch-slurm/squeue.go b/services/crunch-dispatch-slurm/squeue.go
index d22e02597b..eae21e62b6 100644
--- a/services/crunch-dispatch-slurm/squeue.go
+++ b/services/crunch-dispatch-slurm/squeue.go
@@ -6,28 +6,36 @@ package main
 
 import (
 	"bytes"
-	"log"
-	"os/exec"
+	"fmt"
+	"sort"
 	"strings"
 	"sync"
 	"time"
 )
 
-// Squeue implements asynchronous polling monitor of the SLURM queue using the
-// command 'squeue'.
-type SqueueChecker struct {
-	Period    time.Duration
-	uuids     map[string]bool
-	startOnce sync.Once
-	done      chan struct{}
-	sync.Cond
-}
+const slurm15NiceLimit int64 = 10000
 
-func squeueFunc() *exec.Cmd {
-	return exec.Command("squeue", "--all", "--format=%j")
+type slurmJob struct {
+	uuid         string
+	wantPriority int64
+	priority     int64 // current slurm priority (incorporates nice value)
+	nice         int64 // current slurm nice value
+	hitNiceLimit bool
 }
 
-var squeueCmd = squeueFunc
+// SqueueChecker implements asynchronous polling monitor of the SLURM queue
+// using the command 'squeue'.
+type SqueueChecker struct {
+	Logger         logger
+	Period         time.Duration
+	PrioritySpread int64
+	Slurm          Slurm
+	queue          map[string]*slurmJob
+	startOnce      sync.Once
+	done           chan struct{}
+	lock           sync.RWMutex
+	notify         sync.Cond
+}
 
 // HasUUID checks if a given container UUID is in the slurm queue.
 // This does not run squeue directly, but instead blocks until woken
@@ -35,12 +43,87 @@ var squeueCmd = squeueFunc
 func (sqc *SqueueChecker) HasUUID(uuid string) bool {
 	sqc.startOnce.Do(sqc.start)
 
-	sqc.L.Lock()
-	defer sqc.L.Unlock()
+	sqc.lock.RLock()
+	defer sqc.lock.RUnlock()
 
 	// block until next squeue broadcast signaling an update.
-	sqc.Wait()
-	return sqc.uuids[uuid]
+	sqc.notify.Wait()
+	_, exists := sqc.queue[uuid]
+	return exists
+}
+
+// SetPriority sets or updates the desired (Arvados) priority for a
+// container.
+func (sqc *SqueueChecker) SetPriority(uuid string, want int64) {
+	sqc.startOnce.Do(sqc.start)
+
+	sqc.lock.RLock()
+	job := sqc.queue[uuid]
+	if job == nil {
+		// Wait in case the slurm job was just submitted and
+		// will appear in the next squeue update.
+		sqc.notify.Wait()
+		job = sqc.queue[uuid]
+	}
+	needUpdate := job != nil && job.wantPriority != want
+	sqc.lock.RUnlock()
+
+	if needUpdate {
+		sqc.lock.Lock()
+		job.wantPriority = want
+		sqc.lock.Unlock()
+	}
+}
+
+// adjust slurm job nice values as needed to ensure slurm priority
+// order matches Arvados priority order.
+func (sqc *SqueueChecker) reniceAll() {
+	// This is slow (it shells out to scontrol many times) and no
+	// other goroutines update sqc.queue or any of the job fields
+	// we use here, so we don't acquire a lock.
+	jobs := make([]*slurmJob, 0, len(sqc.queue))
+	for _, j := range sqc.queue {
+		if j.wantPriority == 0 {
+			// SLURM job with unknown Arvados priority
+			// (perhaps it's not an Arvados job)
+			continue
+		}
+		if j.priority <= 2*slurm15NiceLimit {
+			// SLURM <= 15.x implements "hold" by setting
+			// priority to 0. If we include held jobs
+			// here, we'll end up trying to push other
+			// jobs below them using negative priority,
+			// which won't help anything.
+			continue
+		}
+		jobs = append(jobs, j)
+	}
+
+	sort.Slice(jobs, func(i, j int) bool {
+		if jobs[i].wantPriority != jobs[j].wantPriority {
+			return jobs[i].wantPriority > jobs[j].wantPriority
+		}
+		// break ties with container uuid --
+		// otherwise, the ordering would change from
+		// one interval to the next, and we'd do many
+		// pointless slurm queue rearrangements.
+		return jobs[i].uuid > jobs[j].uuid
+	})
+	renice := wantNice(jobs, sqc.PrioritySpread)
+	for i, job := range jobs {
+		niceNew := renice[i]
+		if job.hitNiceLimit && niceNew > slurm15NiceLimit {
+			niceNew = slurm15NiceLimit
+		}
+		if niceNew == job.nice {
+			continue
+		}
+		err := sqc.Slurm.Renice(job.uuid, niceNew)
+		if err != nil && niceNew > slurm15NiceLimit && strings.Contains(err.Error(), "Invalid nice value") {
+			sqc.Logger.Warnf("container %q clamping nice values at %d, priority order will not be correct -- see https://dev.arvados.org/projects/arvados/wiki/SLURM_integration#Limited-nice-values-SLURM-15", job.uuid, slurm15NiceLimit)
+			job.hitNiceLimit = true
+		}
+	}
 }
 
 // Stop stops the squeue monitoring goroutine. Do not call HasUUID
@@ -52,36 +135,78 @@ func (sqc *SqueueChecker) Stop() {
 }
 
 // check gets the names of jobs in the SLURM queue (running and
-// queued). If it succeeds, it updates squeue.uuids and wakes up any
+// queued). If it succeeds, it updates sqc.queue and wakes up any
 // goroutines that are waiting in HasUUID() or All().
 func (sqc *SqueueChecker) check() {
-	// Mutex between squeue sync and running sbatch or scancel.  This
-	// establishes a sequence so that squeue doesn't run concurrently with
-	// sbatch or scancel; the next update of squeue will occur only after
-	// sbatch or scancel has completed.
-	sqc.L.Lock()
-	defer sqc.L.Unlock()
-
-	cmd := squeueCmd()
+	cmd := sqc.Slurm.QueueCommand([]string{"--all", "--noheader", "--format=%j %y %Q %T %r"})
 	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
 	cmd.Stdout, cmd.Stderr = stdout, stderr
 	if err := cmd.Run(); err != nil {
-		log.Printf("Error running %q %q: %s %q", cmd.Path, cmd.Args, err, stderr.String())
+		sqc.Logger.Warnf("Error running %q %q: %s %q", cmd.Path, cmd.Args, err, stderr.String())
 		return
 	}
 
-	uuids := strings.Split(stdout.String(), "\n")
-	sqc.uuids = make(map[string]bool, len(uuids))
-	for _, uuid := range uuids {
-		sqc.uuids[uuid] = true
+	lines := strings.Split(stdout.String(), "\n")
+	newq := make(map[string]*slurmJob, len(lines))
+	for _, line := range lines {
+		if line == "" {
+			continue
+		}
+		var uuid, state, reason string
+		var n, p int64
+		if _, err := fmt.Sscan(line, &uuid, &n, &p, &state, &reason); err != nil {
+			sqc.Logger.Warnf("ignoring unparsed line in squeue output: %q", line)
+			continue
+		}
+
+		// No other goroutines write to jobs' priority or nice
+		// fields, so we can read and write them without
+		// locks.
+		replacing, ok := sqc.queue[uuid]
+		if !ok {
+			replacing = &slurmJob{uuid: uuid}
+		}
+		replacing.priority = p
+		replacing.nice = n
+		newq[uuid] = replacing
+
+		if state == "PENDING" && ((reason == "BadConstraints" && p <= 2*slurm15NiceLimit) || reason == "launch failed requeued held") && replacing.wantPriority > 0 {
+			// When using SLURM 14.x or 15.x, our queued
+			// jobs land in this state when "scontrol
+			// reconfigure" invalidates their feature
+			// constraints by clearing all node features.
+			// They stay in this state even after the
+			// features reappear, until we run "scontrol
+			// release {jobid}". Priority is usually 0 in
+			// this state, but sometimes (due to a race
+			// with nice adjustments?) it's a small
+			// positive value.
+			//
+			// "scontrol release" is silent and successful
+			// regardless of whether the features have
+			// reappeared, so rather than second-guessing
+			// whether SLURM is ready, we just keep trying
+			// this until it works.
+			//
+			// "launch failed requeued held" seems to be
+			// another manifestation of this problem,
+			// resolved the same way.
+			sqc.Logger.Printf("releasing held job %q (priority=%d, state=%q, reason=%q)", uuid, p, state, reason)
+			sqc.Slurm.Release(uuid)
+		} else if state != "RUNNING" && p <= 2*slurm15NiceLimit && replacing.wantPriority > 0 {
+			sqc.Logger.Warnf("job %q has low priority %d, nice %d, state %q, reason %q", uuid, p, n, state, reason)
+		}
 	}
-	sqc.Broadcast()
+	sqc.lock.Lock()
+	sqc.queue = newq
+	sqc.lock.Unlock()
+	sqc.notify.Broadcast()
 }
 
 // Initialize, and start a goroutine to call check() once per
 // squeue.Period until terminated by calling Stop().
 func (sqc *SqueueChecker) start() {
-	sqc.L = &sync.Mutex{}
+	sqc.notify.L = sqc.lock.RLocker()
 	sqc.done = make(chan struct{})
 	go func() {
 		ticker := time.NewTicker(sqc.Period)
@@ -92,6 +217,16 @@ func (sqc *SqueueChecker) start() {
 				return
 			case <-ticker.C:
 				sqc.check()
+				sqc.reniceAll()
+				select {
+				case <-ticker.C:
+					// If this iteration took
+					// longer than sqc.Period,
+					// consume the next tick and
+					// wait. Otherwise we would
+					// starve other goroutines.
+				default:
+				}
 			}
 		}
 	}()
@@ -101,12 +236,12 @@ func (sqc *SqueueChecker) start() {
 // names reported by squeue.
 func (sqc *SqueueChecker) All() []string {
 	sqc.startOnce.Do(sqc.start)
-	sqc.L.Lock()
-	defer sqc.L.Unlock()
-	sqc.Wait()
+	sqc.lock.RLock()
+	defer sqc.lock.RUnlock()
+	sqc.notify.Wait()
 	var uuids []string
-	for uuid := range sqc.uuids {
-		uuids = append(uuids, uuid)
+	for u := range sqc.queue {
+		uuids = append(uuids, u)
 	}
 	return uuids
 }