Add saturation metric for executors.

This should make it easier to observe bottlenecks in one of the
underlying executor threads used in the "field writer" SequencedTaskExecutor.

2 files changed, 5 insertions, 0 deletions

diff --git a/searchcore/src/vespa/searchcore/proton/metrics/executor_metrics.cpp b/searchcore/src/vespa/searchcore/proton/metrics/executor_metrics.cpp
index 7c4dcf434a3..b7079542c06 100644
--- a/searchcore/src/vespa/searchcore/proton/metrics/executor_metrics.cpp
+++ b/searchcore/src/vespa/searchcore/proton/metrics/executor_metrics.cpp
@@ -11,6 +11,7 @@ ExecutorMetrics::update(const vespalib::ExecutorStats &stats)
     rejected.inc(stats.rejectedTasks);
     wakeupCount.inc(stats.wakeupCount);
     util.set(stats.getUtil());
+    saturation.set(stats.get_saturation());
     const auto & qSize = stats.queueSize;
     queueSize.addValueBatch(qSize.average(), qSize.count(), qSize.min(), qSize.max());
 }
@@ -21,6 +22,9 @@ ExecutorMetrics::ExecutorMetrics(const std::string &name, metrics::MetricSet *pa
       rejected("rejected", {}, "Number of rejected tasks", this),
       wakeupCount("wakeups", {}, "Number of times a worker thread has been woken up", this),
       util("utilization", {}, "Ratio of time the worker threads has been active", this),
+      saturation("saturation", {}, "Ratio indicating how saturated the worker threads has been. "
+                                   "For most executors this ratio is equal to utilization, but for others (e.g SequencedTaskExecutor) "
+                                   " a higher saturation than utilization indicates a bottleneck in a subset of the worker threads.", this),
       queueSize("queuesize", {}, "Size of task queue", this)
 {
 }
diff --git a/searchcore/src/vespa/searchcore/proton/metrics/executor_metrics.h b/searchcore/src/vespa/searchcore/proton/metrics/executor_metrics.h
index af3a27da240..cd6181b108c 100644
--- a/searchcore/src/vespa/searchcore/proton/metrics/executor_metrics.h
+++ b/searchcore/src/vespa/searchcore/proton/metrics/executor_metrics.h
@@ -15,6 +15,7 @@ struct ExecutorMetrics : metrics::MetricSet
     metrics::LongCountMetric   rejected;
     metrics::LongCountMetric   wakeupCount;
     metrics::DoubleValueMetric util;
+    metrics::DoubleValueMetric saturation;
     metrics::LongAverageMetric queueSize;
 
     void update(const vespalib::ExecutorStats &stats);