fix(kernel-stats): don't record Prometheus vatID labels

This is to address a potential scaling issue when we have hundreds
or thousands of vatIDs.  Addressing this allows us to use slightly
better histograms, and defer the detailed performance analysis to
an exported log.

packages/cosmic-swingset/lib/kernel-stats.js

@@ -8,22 +8,32 @@ import {
   KERNEL_STATS_UPDOWN_METRICS,
 } from '@agoric/swingset-vat/src/kernel/metrics';
 
+/**
+ * TODO Would be nice somehow to label the vats individually, but it's too
+ * high cardinality for us unless we can somehow limit the number of active
+ * metrics (many more than 20 vats).
+ */
+const VAT_ID_IS_TOO_HIGH_CARDINALITY = true;
+
 export const DEFAULT_METER_PROVIDER = new MeterProvider();
 
-export const HISTOGRAM_SECONDS_LATENCY_BOUNDARIES = [
-  0.005,
-  0.01,
-  0.025,
-  0.05,
-  0.1,
-  0.25,
-  0.5,
-  1,
-  2.5,
+export const HISTOGRAM_MS_LATENCY_BOUNDARIES = [
   5,
   10,
+  25,
+  50,
+  100,
+  250,
+  500,
+  1000,
+  2500,
+  5000,
+  10000,
   Infinity,
 ];
+export const HISTOGRAM_SECONDS_LATENCY_BOUNDARIES = HISTOGRAM_MS_LATENCY_BOUNDARIES.map(
+  ms => ms / 1000,
+);
 
 const wrapDeltaMS = (finisher, useDeltaMS) => {
   const startMS = Date.now();
@@ -48,18 +58,21 @@ export function makeSlogCallbacks({ metricMeter, labels }) {
     'swingset_vat_startup',
     metricMeter.createValueRecorder('swingset_vat_startup', {
       description: 'Vat startup time (ms)',
+      boundaries: HISTOGRAM_MS_LATENCY_BOUNDARIES,
     }),
   );
   nameToBaseMetric.init(
     'swingset_vat_delivery',
     metricMeter.createValueRecorder('swingset_vat_delivery', {
       description: 'Vat delivery time (ms)',
+      boundaries: HISTOGRAM_MS_LATENCY_BOUNDARIES,
     }),
   );
   nameToBaseMetric.init(
     'swingset_meter_usage',
     metricMeter.createValueRecorder('swingset_meter_usage', {
       description: 'Vat meter usage',
+      boundaries: HISTOGRAM_MS_LATENCY_BOUNDARIES,
     }),
   );
   const groupToMetrics = makeStore('metricGroup');
@@ -72,21 +85,23 @@ export function makeSlogCallbacks({ metricMeter, labels }) {
    * @param {Record<string, string>} [instance] the specific metric labels
    * @returns {any} the labelled metric
    */
-  const getGroupedMetric = (name, group = {}, instance = {}) => {
+  const getGroupedMetric = (name, group = undefined, instance = {}) => {
     let nameToMetric;
-    const groupKey = recordToKey(group);
+    const groupKey = group && recordToKey(group);
     const instanceKey = recordToKey(instance);
     if (groupToMetrics.has(groupKey)) {
       let oldInstanceKey;
       [nameToMetric, oldInstanceKey] = groupToMetrics.get(groupKey);
-      if (instanceKey !== oldInstanceKey) {
-        for (const metric of nameToMetric.values()) {
-          // FIXME: Delete all the metrics of the old instance.
-          metric;
+      if (group) {
+        if (instanceKey !== oldInstanceKey) {
+          for (const metric of nameToMetric.values()) {
+            // FIXME: Delete all the metrics of the old instance.
+            metric;
+          }
+          // Refresh the metric group.
+          nameToMetric = makeStore('metricName');
+          groupToMetrics.set(groupKey, [nameToMetric, instanceKey]);
         }
-        // Refresh the metric group.
-        nameToMetric = makeStore('metricName');
-        groupToMetrics.set(groupKey, [nameToMetric, instanceKey]);
       }
     } else {
       nameToMetric = makeStore('metricName');
@@ -106,24 +121,38 @@ export function makeSlogCallbacks({ metricMeter, labels }) {
     return metric;
   };
 
+  /**
+   * Return the vat metric group that should be reset when the stats change.
+   *
+   * @param {string} vatID
+   * @returns {Record<string,string> | undefined}
+   */
+  const getVatGroup = vatID => {
+    if (VAT_ID_IS_TOO_HIGH_CARDINALITY) {
+      return undefined;
+    }
+    return { vatID };
+  };
+
   /**
    * Measure some interesting stats.  We currently do a per-vat recording of
    * time spent in the vat for startup and delivery.
    */
   const slogCallbacks = {
     startup(_method, [vatID], finisher) {
       return wrapDeltaMS(finisher, deltaMS => {
-        getGroupedMetric('swingset_vat_startup', { vatID }).record(deltaMS);
+        const group = getVatGroup(vatID);
+        getGroupedMetric('swingset_vat_startup', group).record(deltaMS);
       });
     },
     delivery(_method, [vatID], finisher) {
       return wrapDeltaMS(
         finisher,
         (deltaMS, [[_status, _problem, meterUsage]]) => {
-          getGroupedMetric('swingset_vat_delivery', { vatID }).record(deltaMS);
+          const group = getVatGroup(vatID);
+          getGroupedMetric('swingset_vat_delivery', group).record(deltaMS);
           if (meterUsage) {
             // Add to aggregated metering stats.
-            const group = { vatID };
             for (const [key, value] of Object.entries(meterUsage)) {
               if (key === 'meterType') {
                 // eslint-disable-next-line no-continue