serverless: Model cold start delays

6 files changed, 181 insertions, 5 deletions

diff --git a/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/SimFunctionDeployer.kt b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/SimFunctionDeployer.kt
index fd9d910a..2945a279 100644
--- a/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/SimFunctionDeployer.kt
+++ b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/SimFunctionDeployer.kt
@@ -28,6 +28,7 @@ import org.opendc.serverless.service.FunctionObject
 import org.opendc.serverless.service.deployer.FunctionDeployer
 import org.opendc.serverless.service.deployer.FunctionInstance
 import org.opendc.serverless.service.deployer.FunctionInstanceState
+import org.opendc.serverless.simulator.delay.DelayInjector
 import org.opendc.serverless.simulator.workload.SimServerlessWorkloadMapper
 import org.opendc.simulator.compute.SimBareMetalMachine
 import org.opendc.simulator.compute.SimMachine
@@ -48,6 +49,7 @@ public class SimFunctionDeployer(
     private val clock: Clock,
     private val scope: CoroutineScope,
     private val model: SimMachineModel,
+    private val delayInjector: DelayInjector,
     private val mapper: SimServerlessWorkloadMapper
 ) : FunctionDeployer {
 
@@ -111,6 +113,8 @@ public class SimFunctionDeployer(
         internal fun start() {
             check(state == FunctionInstanceState.Provisioning) { "Invalid state of function instance" }
             job = scope.launch {
+                delay(delayInjector.getColdStartDelay(this@Instance))
+
                 launch {
                     try {
                         machine.run(workload)
@@ -120,12 +124,11 @@ public class SimFunctionDeployer(
                 }
 
                 while (isActive) {
-                    chan.receive()
-
-                    if (queue.isNotEmpty()) {
-                        state = FunctionInstanceState.Active
+                    if (queue.isEmpty()) {
+                        chan.receive()
                     }
 
+                    state = FunctionInstanceState.Active
                     while (queue.isNotEmpty()) {
                         val request = queue.poll()
                         try {
diff --git a/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/ColdStartModel.kt b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/ColdStartModel.kt
new file mode 100644
index 00000000..f9f3718e
--- /dev/null
+++ b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/ColdStartModel.kt
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.serverless.simulator.delay
+
+/**
+ * Model parameters for the cold start times of serverless services.
+ */
+public enum class ColdStartModel {
+    // Min and max memory values from [Peeking Behind The Curtains of Serverless Platforms][2018],
+    // other values deduced from linear curve.
+    LAMBDA {
+        override fun coldStartParam(provisionedMemory: Int): Pair<Double, Double> {
+            return when (provisionedMemory) {
+                128 -> Pair(265.21, 354.43)
+                256 -> Pair(261.46, 334.23)
+                512 -> Pair(257.71, 314.03)
+                1024 -> Pair(253.96, 293.83)
+                1536 -> Pair(250.07, 273.63)
+                2048 -> Pair(246.11, 253.43)
+                else -> Pair(0.0, 1.0)
+            }
+        }
+    },
+    AZURE {
+        // Azure by default uses 1.5gb memory to instantiate functions
+        override fun coldStartParam(provisionedMemory: Int): Pair<Double, Double> {
+            return Pair(242.66, 340.67)
+        }
+    },
+
+    GOOGLE {
+        override fun coldStartParam(provisionedMemory: Int): Pair<Double, Double> {
+            return when (provisionedMemory) {
+                128 -> Pair(493.04, 345.8)
+                256 -> Pair(416.59, 301.5)
+                512 -> Pair(340.14, 257.2)
+                1024 -> Pair(263.69, 212.9)
+                1536 -> Pair(187.24, 168.6)
+                2048 -> Pair(110.77, 124.3)
+                else -> Pair(0.0, 1.0)
+            }
+        }
+    };
+
+    /**
+     * Obtain the stochastic parameters for the cold start models.
+     */
+    public abstract fun coldStartParam(provisionedMemory: Int): Pair<Double, Double>
+}
diff --git a/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/DelayInjector.kt b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/DelayInjector.kt
new file mode 100644
index 00000000..f882031b
--- /dev/null
+++ b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/DelayInjector.kt
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.serverless.simulator.delay
+
+import org.opendc.serverless.service.deployer.FunctionInstance
+
+/**
+ * An interface for modeling the delay caused by function cold starts.
+ */
+public interface DelayInjector {
+    /**
+     * Returns the cold start delay duration sampled from a normal distribution, the distribution is
+     * initialized using custom mean and standard deviation based on provisioned memory, language and
+     * failure model
+     */
+    public fun getColdStartDelay(instance: FunctionInstance): Long
+}
diff --git a/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/StochasticDelayInjector.kt b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/StochasticDelayInjector.kt
new file mode 100644
index 00000000..154378e1
--- /dev/null
+++ b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/StochasticDelayInjector.kt
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.serverless.simulator.delay
+
+import org.opendc.serverless.service.deployer.FunctionInstance
+import java.util.*
+import kotlin.math.abs
+
+/*
+ * Interface for instance deployment delay estimation.
+ */
+public class StochasticDelayInjector(private val model: ColdStartModel, private val random: Random) : DelayInjector {
+    override fun getColdStartDelay(instance: FunctionInstance): Long {
+        val (mean, sd) = model.coldStartParam(instance.function.memorySize.toInt())
+        return abs(random.nextGaussian() * sd + mean).toLong()
+    }
+}
diff --git a/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/ZeroDelayInjector.kt b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/ZeroDelayInjector.kt
new file mode 100644
index 00000000..0895ee18
--- /dev/null
+++ b/simulator/opendc-serverless/opendc-serverless-simulator/src/main/kotlin/org/opendc/serverless/simulator/delay/ZeroDelayInjector.kt
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.serverless.simulator.delay
+
+import org.opendc.serverless.service.deployer.FunctionInstance
+
+public object ZeroDelayInjector : DelayInjector {
+    override fun getColdStartDelay(instance: FunctionInstance): Long = 0
+}
diff --git a/simulator/opendc-serverless/opendc-serverless-simulator/src/test/kotlin/org/opendc/serverless/simulator/SimServerlessServiceTest.kt b/simulator/opendc-serverless/opendc-serverless-simulator/src/test/kotlin/org/opendc/serverless/simulator/SimServerlessServiceTest.kt
index 89998585..3a070475 100644
--- a/simulator/opendc-serverless/opendc-serverless-simulator/src/test/kotlin/org/opendc/serverless/simulator/SimServerlessServiceTest.kt
+++ b/simulator/opendc-serverless/opendc-serverless-simulator/src/test/kotlin/org/opendc/serverless/simulator/SimServerlessServiceTest.kt
@@ -34,6 +34,7 @@ import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertAll
 import org.opendc.serverless.service.ServerlessService
 import org.opendc.serverless.service.router.RandomRoutingPolicy
+import org.opendc.serverless.simulator.delay.ZeroDelayInjector
 import org.opendc.serverless.simulator.workload.SimServerlessWorkload
 import org.opendc.simulator.compute.SimMachineModel
 import org.opendc.simulator.compute.model.MemoryUnit
@@ -68,7 +69,7 @@ internal class SimServerlessServiceTest {
         val workload = spyk(object : SimServerlessWorkload, SimWorkload by SimFlopsWorkload(1000) {
             override suspend fun invoke() {}
         })
-        val deployer = SimFunctionDeployer(clock, this, machineModel) { workload }
+        val deployer = SimFunctionDeployer(clock, this, machineModel, ZeroDelayInjector) { workload }
         val service = ServerlessService(coroutineContext, clock, meter, deployer, RandomRoutingPolicy())
 
         val client = service.newClient()