feat: config option for selecting the scheduling strategy

nextflow/plugins/nf-k8s/src/main/nextflow/k8s/K8sConfig.groovy

@@ -242,6 +242,12 @@ class K8sConfig implements ConfigScope {
     """)
     final String runtimeRecordPath
 
+    @ConfigOption
+    @Description("""
+        Selects a scheduling strategy
+    """)
+    final String schedulingStrategy
+
     /* required by extension point -- do not remove */
     K8sConfig() {
         this(Collections.emptyMap())
@@ -280,6 +286,8 @@ class K8sConfig implements ConfigScope {
         workDir = opts.workDir ?: "${launchDir}/work"
         runtimeRecordPath = opts.runtimeRecordPath as String ?: "${workDir}/runtimes.csv"
 
+        schedulingStrategy = opts.schedulingStrategy as String ?: "Hash"
+
         // -- shortcut to pod image pull-policy
         if( imagePullPolicy )
             pod.imagePullPolicy = imagePullPolicy

nextflow/plugins/nf-k8s/src/main/nextflow/k8s/K8sExecutor.groovy

@@ -17,6 +17,7 @@
 package nextflow.k8s
 
 import groovy.transform.CompileDynamic
+import nextflow.k8s.strategies.K8sDVFSSchedulingStrategy
 import nextflow.k8s.strategies.K8sHashSchedulingStrategy
 
 import java.util.concurrent.TimeUnit
@@ -98,7 +99,17 @@ class K8sExecutor extends Executor implements ExtensionPoint {
         this.runtimeRecorder = new K8sRuntimeRecorder(k8sConfig.recordTaskRuntimes, k8sConfig.runtimeRecordPath)
         this.runtimeEstimator = new K8sRuntimeEstimator(k8sConfig.runtimeRecordPath)
 
-        this.taskScheduler = new K8sTaskScheduler(getNodeList(), new K8sHashSchedulingStrategy())
+        K8sSchedulingStrategy strategy = null
+        if (k8sConfig.schedulingStrategy == "Hash") {
+            strategy = new K8sHashSchedulingStrategy()
+        } else if (k8sConfig.schedulingStrategy == "DVFS") {
+            strategy = new K8sDVFSSchedulingStrategy()
+        } else {
+            log.error "[K8s] invalid scheduling strategy $k8sConfig.schedulingStrategy, falling back on \"Hash\""
+            strategy = new K8sHashSchedulingStrategy()
+        }
+
+        this.taskScheduler = new K8sTaskScheduler(getNodeList(), strategy)
         this.schedulerThread = new Thread(this.taskScheduler)
         this.schedulerThread.start()
     }

nextflow/plugins/nf-k8s/src/main/nextflow/k8s/strategies/K8sDVFSSchedulingStrategy.groovy

@@ -0,0 +1,22 @@
+package nextflow.k8s.strategies
+
+import nextflow.k8s.K8sSchedulingDecision
+import nextflow.k8s.K8sSchedulingRequest
+import nextflow.k8s.K8sSchedulingStrategy
+import nextflow.k8s.K8sTaskScheduler
+
+/**
+ * Implements a scheduling strategy utilizing dvfs to reduce the energy consumption
+ * of workflow execution, while attempting to maintain the same makespan.
+ */
+class K8sDVFSSchedulingStrategy implements K8sSchedulingStrategy {
+    @Override
+    K8sSchedulingDecision schedule(K8sTaskScheduler scheduler, List<K8sSchedulingRequest> queue) {
+        return null
+    }
+
+    @Override
+    boolean scheduleImmediately(K8sTaskScheduler scheduler, List<K8sSchedulingRequest> queue) {
+        return false
+    }
+}