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fn: agent slot improvements (#704)

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*) Stopped using latency previous/current stats, this
was not working as expected. Fresh starts usually have
these stats zero for a long time, and initial samples
are high due to downloads, caches, etc.

*) New state to track: containers that are idle. In other
words, containers that have an unused token in the slot
queue.

*) Removed latency counts since these are not used in
container start decision anymore. Simplifies logs.

*) isNewContainerNeeded() simplified to use idle count
to estimate effective waiters. Removed speculative
latency based logic and progress check comparison.
In agent, waitHot() delayed signalling compansates
for these changes. If the estimation may fail, but
this should correct itself in the next 200 msec
signal.
This commit is contained in:
Tolga Ceylan
2018-01-19 12:35:52 -08:00
committed by GitHub
parent f2b15299d9
commit 8c31e47c01
3 changed files with 60 additions and 117 deletions
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76
api/agent/slots_test.go
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@@ -174,74 +174,50 @@ func TestSlotQueueBasic2(t *testing.T) {
}
}
func statsHelperSet(runC, startC, waitC, runL, startL, waitL uint64) slotQueueStats {
func statsHelperSet(runC, startC, waitC, idleC uint64) slotQueueStats {
return slotQueueStats{
states: [SlotQueueLast]uint64{runC, startC, waitC},
latencies: [SlotQueueLast]uint64{runL, startL, waitL},
states: [SlotQueueLast]uint64{runC, startC, waitC, idleC},
}
}
func TestSlotNewContainerLogic1(t *testing.T) {
var cur slotQueueStats
var prev slotQueueStats
cur = statsHelperSet(0, 0, 0, 0, 0, 0)
prev = statsHelperSet(0, 0, 0, 0, 0, 0)
// CASE I: There's no one waiting despite cur == prev
if isNewContainerNeeded(&cur, &prev) {
t.Fatalf("Should not need a new container cur: %#v prev: %#v", cur, prev)
cur = statsHelperSet(0, 0, 0, 0)
// CASE: There's no one waiting
if isNewContainerNeeded(&cur) {
t.Fatalf("Should not need a new container cur: %#v", cur)
}
// CASE II: There are starters >= waiters
cur = statsHelperSet(0, 10, 1, 0, 0, 0)
prev = statsHelperSet(0, 10, 1, 0, 0, 0)
if isNewContainerNeeded(&cur, &prev) {
t.Fatalf("Should not need a new container cur: %#v prev: %#v", cur, prev)
// CASE: There are starters >= waiters
cur = statsHelperSet(1, 10, 10, 0)
if isNewContainerNeeded(&cur) {
t.Fatalf("Should not need a new container cur: %#v", cur)
}
// CASE III: no executors
cur = statsHelperSet(0, 0, 1, 0, 0, 0)
prev = statsHelperSet(0, 0, 1, 0, 0, 0)
if !isNewContainerNeeded(&cur, &prev) {
t.Fatalf("Should need a new container cur: %#v prev: %#v", cur, prev)
// CASE: There are starters < waiters
cur = statsHelperSet(1, 5, 10, 0)
if !isNewContainerNeeded(&cur) {
t.Fatalf("Should need a new container cur: %#v", cur)
}
// CASE IV: cur == prev same, progress has stalled, with waiters and
// small num of executors
cur = statsHelperSet(2, 0, 10, 0, 0, 0)
prev = statsHelperSet(2, 0, 10, 0, 0, 0)
if !isNewContainerNeeded(&cur, &prev) {
t.Fatalf("Should need a new container cur: %#v prev: %#v", cur, prev)
// CASE: effective waiters 0 (idle = waiter = 10)
cur = statsHelperSet(11, 0, 10, 10)
if isNewContainerNeeded(&cur) {
t.Fatalf("Should not need a new container cur: %#v", cur)
}
// CASE V: cur != prev, runLat/executors*2 < waitLat
// Let's make cur and prev unequal to prevent blocked progress detection
cur = statsHelperSet(2, 0, 10, 12, 100, 13)
prev = statsHelperSet(2, 0, 10, 12, 101, 13)
if !isNewContainerNeeded(&cur, &prev) {
t.Fatalf("Should need a new container cur: %#v prev: %#v", cur, prev)
// CASE: effective waiters > 0 (idle = 5 waiter = 10)
cur = statsHelperSet(11, 0, 10, 5)
if !isNewContainerNeeded(&cur) {
t.Fatalf("Should need a new container cur: %#v", cur)
}
// CASE VI: cur != prev, runLat < waitLat
cur = statsHelperSet(1, 0, 10, 12, 100, 14)
prev = statsHelperSet(1, 0, 10, 12, 101, 14)
if !isNewContainerNeeded(&cur, &prev) {
t.Fatalf("Should need a new container cur: %#v prev: %#v", cur, prev)
}
// CAST VII: cur != prev, startLat < waitLat
cur = statsHelperSet(1, 0, 10, 2, 10, 20)
prev = statsHelperSet(1, 0, 10, 1, 11, 20)
if !isNewContainerNeeded(&cur, &prev) {
t.Fatalf("Should need a new container cur: %#v prev: %#v", cur, prev)
}
// CAST VIII: cur != prev, fallback
cur = statsHelperSet(1, 0, 10, 2, 10, 2)
prev = statsHelperSet(1, 0, 10, 1, 11, 2)
if isNewContainerNeeded(&cur, &prev) {
t.Fatalf("Should not need a new container cur: %#v prev: %#v", cur, prev)
// CASE: no executors, but 1 waiter
cur = statsHelperSet(0, 0, 1, 0)
if !isNewContainerNeeded(&cur) {
t.Fatalf("Should need a new container cur: %#v", cur)
}
}