feat: use inspector for heap profiles #236
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,180 @@ | ||
| import * as inspector from 'node:inspector'; | ||
| import {AllocationProfileNode, Allocation} from './v8-types'; | ||
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| const session = new inspector.Session(); | ||
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| export interface SamplingHeapProfileSample { | ||
| size: number; | ||
| nodeId: number; | ||
| ordinal: number; | ||
| } | ||
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| export interface SamplingHeapProfileNode { | ||
| callFrame: inspector.Runtime.CallFrame; | ||
| selfSize: number; | ||
| id: number; | ||
| children: SamplingHeapProfileNode[]; | ||
| } | ||
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| /** | ||
| * Need to create this interface since the type definitions file for node inspector | ||
| * at https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/node/inspector.d.ts | ||
| * has not been updated with the latest changes yet. | ||
| * | ||
| * The types defined through this interface are in sync with the documentation found at - | ||
| * https://chromedevtools.github.io/devtools-protocol/v8/HeapProfiler/ | ||
| */ | ||
| export interface CompatibleSamplingHeapProfile { | ||
| head: SamplingHeapProfileNode; | ||
| samples: SamplingHeapProfileSample[]; | ||
| } | ||
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| export function startSamplingHeapProfiler( | ||
| heapIntervalBytes: number, | ||
| stackDepth: number | ||
|
There was a problem hiding this comment. Please remove "stack depth", since it's no longer in use. |
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| ): Promise<void> { | ||
| session.connect(); | ||
| return new Promise<void>((resolve, reject) => { | ||
| session.post( | ||
| 'HeapProfiler.startSampling', | ||
| {heapIntervalBytes}, | ||
| (err: Error | null): void => { | ||
| if (err !== null) { | ||
| console.error(`Error starting heap sampling: ${err}`); | ||
|
There was a problem hiding this comment. Nothing should be logged within this repo (cloud-profiler-nodejs will log errors occurring; logging anything directly here will either result in things being double logged, or prevent users from being able to control what is logged) |
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| reject(err); | ||
| return; | ||
| } | ||
| console.log( | ||
| `Started Heap Sampling with interval bytes ${heapIntervalBytes}` | ||
| ); | ||
| resolve(); | ||
| } | ||
| ); | ||
| }); | ||
| } | ||
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| /** | ||
| * Stops the sampling heap profile and discards the current profile. | ||
| */ | ||
| export function stopSamplingHeapProfiler(): Promise<void> { | ||
| return new Promise<void>((resolve, reject) => { | ||
| session.post( | ||
| 'HeapProfiler.stopSampling', | ||
| ( | ||
| err: Error | null, | ||
| profile: inspector.HeapProfiler.StopSamplingReturnType | ||
| ) => { | ||
| if (err !== null) { | ||
| console.error(`Error stopping heap sampling ${err}`); | ||
| reject(err); | ||
| return; | ||
| } | ||
| console.log( | ||
| `Stopped sampling heap, discarding current profile: ${profile}` | ||
| ); | ||
| session.disconnect(); | ||
| console.log('Disconnected from current profiling session'); | ||
| resolve(); | ||
| } | ||
| ); | ||
| }); | ||
| } | ||
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| export async function getAllocationProfile(): Promise<AllocationProfileNode> { | ||
| return new Promise<AllocationProfileNode>((resolve, reject) => { | ||
| session.post( | ||
| 'HeapProfiler.getSamplingProfile', | ||
| ( | ||
| err: Error | null, | ||
| result: inspector.HeapProfiler.GetSamplingProfileReturnType | ||
| ) => { | ||
| if (err !== null) { | ||
| console.error(`Error getting sampling profile ${err}`); | ||
| reject(err); | ||
| return; | ||
| } | ||
| const compatibleHeapProfile = | ||
| result.profile as CompatibleSamplingHeapProfile; | ||
| resolve( | ||
| translateToAllocationProfileNode( | ||
| compatibleHeapProfile.head, | ||
|
There was a problem hiding this comment. Nit since these are the only two fields in compatibleHeapProfile, just pass it directly here |
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| compatibleHeapProfile.samples | ||
| ) | ||
| ); | ||
| } | ||
| ); | ||
| }); | ||
| } | ||
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| function translateToAllocationProfileNode( | ||
| node: SamplingHeapProfileNode, | ||
| samples: SamplingHeapProfileSample[] | ||
| ): AllocationProfileNode { | ||
| const allocationProfileNode: AllocationProfileNode = { | ||
| allocations: [], | ||
| name: node.callFrame.functionName, | ||
| scriptName: node.callFrame.url, | ||
| scriptId: Number(node.callFrame.scriptId), | ||
| lineNumber: node.callFrame.lineNumber, | ||
| columnNumber: node.callFrame.columnNumber, | ||
| children: [], | ||
| }; | ||
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| const children: AllocationProfileNode[] = new Array<AllocationProfileNode>( | ||
|
There was a problem hiding this comment.
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| node.children.length | ||
| ); | ||
| for (let i = 0; i < node.children.length; i++) { | ||
| children.splice( | ||
| i, | ||
| 1, | ||
| translateToAllocationProfileNode(node.children[i], samples) | ||
| ); | ||
| } | ||
| allocationProfileNode.children = children; | ||
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| // find all samples belonging to this node Id | ||
| const samplesForCurrentNodeId: SamplingHeapProfileSample[] = | ||
| filterSamplesBasedOnNodeId(node.id, samples); | ||
| const mappedAllocationsForNodeId: Allocation[] = | ||
| createAllocationsFromSamplesForNode(samplesForCurrentNodeId); | ||
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| allocationProfileNode.allocations = mappedAllocationsForNodeId; | ||
| return allocationProfileNode; | ||
| } | ||
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| function filterSamplesBasedOnNodeId( | ||
| nodeId: number, | ||
| samples: SamplingHeapProfileSample[] | ||
| ): SamplingHeapProfileSample[] { | ||
| const filtered = samples.filter((sample: SamplingHeapProfileSample) => { | ||
|
There was a problem hiding this comment. I'd create a map in the outer scope or closure of the recursive function to do this lookup in constant time as this is n^2 now. Check out my PR for cpu time if you don't what i mean |
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| return sample.nodeId === nodeId; | ||
| }); | ||
| return filtered; | ||
| } | ||
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| function createAllocationsFromSamplesForNode( | ||
|
There was a problem hiding this comment. Couldnt this be done once in linear time for all nodes, since the samples already have node ID? Group by node ID then for each group, group by byte sizes being equal? |
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| samplesForNode: SamplingHeapProfileSample[] | ||
| ): Allocation[] { | ||
| const sampleSizeToCountMap = new Map<number, number>(); | ||
| samplesForNode.forEach((sample: SamplingHeapProfileSample) => { | ||
| const currentCountForSize: number | undefined = sampleSizeToCountMap.get( | ||
| sample.size | ||
| ); | ||
| if (currentCountForSize !== undefined) { | ||
| sampleSizeToCountMap.set(sample.size, currentCountForSize + 1); | ||
| } else { | ||
| sampleSizeToCountMap.set(sample.size, 1); | ||
| } | ||
| }); | ||
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| const mappedAllocations: Allocation[] = []; | ||
| sampleSizeToCountMap.forEach((size: number, count: number) => { | ||
| const mappedAllocation: Allocation = { | ||
| sizeBytes: size, | ||
| count: count, | ||
| }; | ||
| mappedAllocations.push(mappedAllocation); | ||
| }); | ||
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| return mappedAllocations; | ||
| } | ||
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You might open an issue in that repo and link it here
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Good point, will do that.