feat(instr-runtime-node): add configurable gcDurationBuckets option

Allow users to customize the histogram bucket boundaries for the
v8js.gc.duration metric via the gcDurationBuckets configuration option,
similar to how monitoringPrecision is configurable.

Author: claude

packages/instrumentation-runtime-node/README.md

@@ -60,9 +60,10 @@ nodejs_performance_event_loop_utilization 0.010140079547955264
 
 `RuntimeNodeInstrumentation`'s constructor accepts the following options:
 
-| name                                        | type  | unit        | default | description                                                                                                                                                                                                                                                                                     |
-|---------------------------------------------|-------|-------------|---------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| [`monitoringPrecision`](./src/types.ts#L25) | `int` | millisecond | `10`    | The approximate number of milliseconds for which to calculate event loop utilization averages. A larger value will result in more accurate averages at the expense of less granular data. Should be set to below the scrape interval of your metrics collector to avoid duplicated data points. |
+| name                                        | type       | unit        | default              | description                                                                                                                                                                                                                                                                                     |
+|---------------------------------------------|------------|-------------|----------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| [`monitoringPrecision`](./src/types.ts#L20) | `int`      | millisecond | `10`                 | The approximate number of milliseconds for which to calculate event loop utilization averages. A larger value will result in more accurate averages at the expense of less granular data. Should be set to below the scrape interval of your metrics collector to avoid duplicated data points. |
+| [`gcDurationBuckets`](./src/types.ts#L21)   | `number[]` | second      | `[0.01, 0.1, 1, 10]` | The histogram bucket boundaries to use for the GC duration histogram (`v8js.gc.duration`). |
 
 ## Useful links
 

packages/instrumentation-runtime-node/src/instrumentation.ts

@@ -27,6 +27,7 @@ import { PACKAGE_VERSION, PACKAGE_NAME } from './version';
 
 const DEFAULT_CONFIG: RuntimeNodeInstrumentationConfig = {
   monitoringPrecision: 10,
+  gcDurationBuckets: [0.01, 0.1, 1, 10],
 };
 
 export class RuntimeNodeInstrumentation extends InstrumentationBase<RuntimeNodeInstrumentationConfig> {

packages/instrumentation-runtime-node/src/metrics/gcCollector.ts

@@ -22,8 +22,6 @@ import { Histogram, ValueType } from '@opentelemetry/api';
 import { BaseCollector } from './baseCollector';
 import { ATTR_V8JS_GC_TYPE, METRIC_V8JS_GC_DURATION } from '../semconv';
 
-const DEFAULT_GC_DURATION_BUCKETS = [0.01, 0.1, 1, 10];
-
 const kinds: string[] = [];
 kinds[perf_hooks.constants.NODE_PERFORMANCE_GC_MAJOR] = 'major';
 kinds[perf_hooks.constants.NODE_PERFORMANCE_GC_MINOR] = 'minor';
@@ -61,7 +59,7 @@ export class GCCollector extends BaseCollector {
         unit: 's',
         valueType: ValueType.DOUBLE,
         advice: {
-          explicitBucketBoundaries: DEFAULT_GC_DURATION_BUCKETS,
+          explicitBucketBoundaries: this._config.gcDurationBuckets,
         },
       }
     );

packages/instrumentation-runtime-node/src/types.ts

@@ -18,4 +18,5 @@ import type { InstrumentationConfig } from '@opentelemetry/instrumentation';
 export interface RuntimeNodeInstrumentationConfig
   extends InstrumentationConfig {
   monitoringPrecision?: number;
+  gcDurationBuckets?: number[];
 }