feat: expose fiber responsiveness metrics (#2125)

Should allow track caches where Dragonfly is not responsive to I/O due to big CPU tasks. Also, update the local grafana dashboard. Signed-off-by: Roman Gershman <roman@dragonflydb.io>
2024-12-14 11:58:02 +00:00 · 2023-11-05 16:56:33 +02:00 · 2023-11-05 16:56:33 +02:00 · c7db025a48
commit c7db025a48
parent b9781c4903
5 changed files with 143 additions and 21 deletions
--- a/2
+++ b/2
@ -1 +1 @@
-Subproject commit fe7ec28642c1b699bdc8839296f354d797ee0365
+Subproject commit 1fea6effc72919649c815afb04e9c7829b0240ab
--- a/src/server/server_family.cc
+++ b/src/server/server_family.cc
@ -850,7 +850,7 @@ void PrintPrometheusMetrics(const Metrics& m, StringResponse* resp) {
  AppendMetricValue("role", 1, {"role"}, {m.is_master ? "master" : "replica"}, &resp->body());
  AppendMetricWithoutLabels("master", "1 if master 0 if replica", m.is_master ? 1 : 0,
                            MetricType::GAUGE, &resp->body());
-  AppendMetricWithoutLabels("uptime_in_seconds", "", m.uptime, MetricType::GAUGE, &resp->body());
+  AppendMetricWithoutLabels("uptime_in_seconds", "", m.uptime, MetricType::COUNTER, &resp->body());

  // Clients metrics
  AppendMetricWithoutLabels("connected_clients", "", m.conn_stats.num_conns, MetricType::GAUGE,
@ -923,7 +923,7 @@ void PrintPrometheusMetrics(const Metrics& m, StringResponse* resp) {
                       &command_metrics);
    for (const auto& [name, stat] : m.cmd_stats_map) {
      const auto calls = stat.first;
-      const auto duration_seconds = stat.second * 0.001;
+      const double duration_seconds = stat.second * 0.001;
      AppendMetricValue("commands_total", calls, {"cmd"}, {name}, &command_metrics);
      AppendMetricValue("commands_duration_seconds_total", duration_seconds, {"cmd"}, {name},
                        &command_metrics);
@ -944,6 +944,18 @@ void PrintPrometheusMetrics(const Metrics& m, StringResponse* resp) {
    absl::StrAppend(&resp->body(), replication_lag_metrics);
  }

+  AppendMetricWithoutLabels("fiber_switch_total", "", m.fiber_switch_cnt, MetricType::COUNTER,
+                            &resp->body());
+  double delay_seconds = m.fiber_switch_delay_ns * 1e-9;
+  AppendMetricWithoutLabels("fiber_switch_delay_seconds_total", "", delay_seconds,
+                            MetricType::COUNTER, &resp->body());
+
+  AppendMetricWithoutLabels("fiber_longrun_total", "", m.fiber_longrun_cnt, MetricType::COUNTER,
+                            &resp->body());
+  double longrun_seconds = m.fiber_longrun_ns * 1e-9;
+  AppendMetricWithoutLabels("fiber_longrun_seconds_total", "", longrun_seconds, MetricType::COUNTER,
+                            &resp->body());
+
  absl::StrAppend(&resp->body(), db_key_metrics);
  absl::StrAppend(&resp->body(), db_key_expire_metrics);
 }
@ -1402,6 +1414,11 @@ Metrics ServerFamily::GetMetrics() const {

    lock_guard lk(mu);

+    result.fiber_switch_cnt += fb2::FiberSwitchEpoch();
+    result.fiber_switch_delay_ns += fb2::FiberSwitchDelay();
+    result.fiber_longrun_cnt += fb2::FiberLongRunCnt();
+    result.fiber_longrun_ns += fb2::FiberLongRunSum();
+
    result.coordinator_stats += ss->stats;
    result.conn_stats += ss->connection_stats;

--- a/src/server/server_family.h
+++ b/src/server/server_family.h
@ -86,6 +86,12 @@ struct Metrics {
  size_t small_string_bytes = 0;
  uint32_t traverse_ttl_per_sec = 0;
  uint32_t delete_ttl_per_sec = 0;
+  uint64_t fiber_switch_cnt = 0;
+  uint64_t fiber_switch_delay_ns = 0;
+
+  // Statistics about fibers running for a long time (more than 1ms).
+  uint64_t fiber_longrun_cnt = 0;
+  uint64_t fiber_longrun_ns = 0;

  std::map<std::string, std::pair<uint64_t, uint64_t>> cmd_stats_map;  // command call frequencies

--- a/tools/local/monitoring/grafana/provisioning/dashboards/dashboard.json
+++ b/tools/local/monitoring/grafana/provisioning/dashboards/dashboard.json
@ -105,7 +105,7 @@
        },
        "textMode": "auto"
      },
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "targets": [
        {
          "datasource": {
@ -191,7 +191,7 @@
        },
        "textMode": "auto"
      },
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "targets": [
        {
          "datasource": {
@ -282,7 +282,7 @@
        "showThresholdLabels": false,
        "showThresholdMarkers": true
      },
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "targets": [
        {
          "datasource": {
@ -350,7 +350,7 @@
        "alertThreshold": true
      },
      "percentage": false,
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "pointradius": 5,
      "points": false,
      "renderer": "flot",
@ -456,7 +456,7 @@
        "alertThreshold": true
      },
      "percentage": false,
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "pointradius": 5,
      "points": false,
      "renderer": "flot",
@ -574,7 +574,7 @@
        "alertThreshold": true
      },
      "percentage": false,
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "pointradius": 5,
      "points": false,
      "renderer": "flot",
@ -690,7 +690,7 @@
        "alertThreshold": true
      },
      "percentage": false,
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "pointradius": 5,
      "points": false,
      "renderer": "flot",
@ -791,7 +791,7 @@
        "alertThreshold": true
      },
      "percentage": false,
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "pointradius": 5,
      "points": false,
      "renderer": "flot",
@ -912,7 +912,7 @@
        "alertThreshold": true
      },
      "percentage": false,
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "pointradius": 5,
      "points": false,
      "renderer": "flot",
@ -1033,7 +1033,7 @@
        "alertThreshold": true
      },
      "percentage": false,
-      "pluginVersion": "10.2.0",
+      "pluginVersion": "9.3.6",
      "pointradius": 2,
      "points": false,
      "renderer": "flot",
@ -1110,7 +1110,6 @@
            "mode": "palette-classic"
          },
          "custom": {
-            "axisBorderShow": false,
            "axisCenteredZero": false,
            "axisColorMode": "text",
            "axisLabel": "",
@ -1124,7 +1123,6 @@
              "tooltip": false,
              "viz": false
            },
-            "insertNulls": false,
            "lineInterpolation": "linear",
            "lineWidth": 1,
            "pointSize": 5,
@ -1155,7 +1153,7 @@
              }
            ]
          },
-          "unit": "µs"
+          "unit": "s"
        },
        "overrides": []
      },
@ -1187,7 +1185,107 @@
          "disableTextWrap": false,
          "editorMode": "code",
          "expr":
-              "rate(dragonfly_fiber_switch_delay_seconds_total[$__rate_interval])*1000000/rate(dragonfly_fiber_switch_total[$__rate_interval])",
+              "rate(dragonfly_fiber_switch_delay_seconds_total[$__rate_interval])/rate(dragonfly_fiber_switch_total[$__rate_interval])",
+          "fullMetaSearch": false,
+          "includeNullMetadata": false,
+          "instant": false,
+          "legendFormat": "__auto",
+          "range": true,
+          "refId": "A",
+          "useBackend": false
+        }
+      ],
+      "title": "FiberSwitchDelay",
+      "transformations": [],
+      "type": "timeseries"
+    },
+    {
+      "datasource": {
+        "type": "prometheus",
+        "uid": "${DS_PROMETHEUS}"
+      },
+      "fieldConfig": {
+        "defaults": {
+          "color": {
+            "mode": "palette-classic"
+          },
+          "custom": {
+            "axisCenteredZero": false,
+            "axisColorMode": "text",
+            "axisLabel": "",
+            "axisPlacement": "auto",
+            "barAlignment": 0,
+            "drawStyle": "line",
+            "fillOpacity": 0,
+            "gradientMode": "none",
+            "hideFrom": {
+              "legend": false,
+              "tooltip": false,
+              "viz": false
+            },
+            "lineInterpolation": "linear",
+            "lineWidth": 1,
+            "pointSize": 5,
+            "scaleDistribution": {
+              "type": "linear"
+            },
+            "showPoints": "auto",
+            "spanNulls": false,
+            "stacking": {
+              "group": "A",
+              "mode": "none"
+            },
+            "thresholdsStyle": {
+              "mode": "off"
+            }
+          },
+          "mappings": [],
+          "thresholds": {
+            "mode": "absolute",
+            "steps": [
+              {
+                "color": "green",
+                "value": null
+              },
+              {
+                "color": "red",
+                "value": 80
+              }
+            ]
+          },
+          "unit": "s"
+        },
+        "overrides": []
+      },
+      "gridPos": {
+        "h": 8,
+        "w": 12,
+        "x": 12,
+        "y": 30
+      },
+      "id": 20,
+      "options": {
+        "legend": {
+          "calcs": [],
+          "displayMode": "list",
+          "placement": "bottom",
+          "showLegend": true
+        },
+        "tooltip": {
+          "mode": "single",
+          "sort": "none"
+        }
+      },
+      "targets": [
+        {
+          "datasource": {
+            "type": "prometheus",
+            "uid": "PBFA97CFB590B2093"
+          },
+          "disableTextWrap": false,
+          "editorMode": "code",
+          "expr":
+              "rate(dragonfly_fiber_longrun_seconds_total[$__rate_interval])/rate(dragonfly_fiber_longrun_total[$__rate_interval])",
          "fullMetaSearch": false,
          "includeNullMetadata": false,
          "instant": false,
@ -1203,7 +1301,8 @@
    }
  ],
  "refresh": "",
-  "schemaVersion": 38,
+  "schemaVersion": 37,
+  "style": "dark",
  "tags": [
    "prometheus",
    "dragonfly"
--- a/tools/local/monitoring/prometheus/prometheus.yml
+++ b/tools/local/monitoring/prometheus/prometheus.yml
@ -29,14 +29,14 @@ scrape_configs:
  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.

  - job_name: dragonfly
-    scrape_interval: 5s
+    scrape_interval: 1s
    static_configs:
      - targets: ['host.docker.internal:6379']

  - job_name: 'prometheus'

    # Override the global default and scrape targets from this job every 5 seconds.
-    scrape_interval: 5s
+    scrape_interval: 1s

    static_configs:
         - targets: ['localhost:9090']
@ -45,7 +45,7 @@ scrape_configs:
  - job_name: 'node-exporter'

    # Override the global default and scrape targets from this job every 5 seconds.
-    scrape_interval: 5s
+    scrape_interval: 1s
    static_configs:
      - targets: ['node-exporter:9100']
        labels: