core(simulator): convert node timings to trace #5350
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cc @benschwarz as a model for simulation->HAR |
lighthouse-core/lib/asset-saver.js
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| @@ -283,6 +436,13 @@ async function saveAssets(artifacts, audits, pathWithBasename) { | |||
| log.log('saveAssets', 'trace file streamed to disk: ' + streamTraceFilename); | |||
| }); | |||
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| for (const [label, nodeTimings] of Simulator.COMPUTED_NODE_TIMINGS) { | |||
| if (!LANTERN_TRACES_TO_SAVE.includes(label) && !process.env.LANTERN_DEBUG) continue; | |||
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let's wrap this whole thing in a conditional to check the env variable.
lighthouse-core/lib/asset-saver.js
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| * @return {LH.TraceEvent} | ||
| */ | ||
| function createFakeTracingStarted() { | ||
| const data = { |
lighthouse-core/lib/asset-saver.js
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| function createFakeTracingStarted() { | ||
| const data = { | ||
| frameTreeNodeId: 1, | ||
| sessionId: '1.1', |
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fwiw, when i did this, sessionId was the only required args.data prop, but this was before persistentIds..
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I'm not sure they're necessary, but they're all present 🤷♂️
lighthouse-core/lib/asset-saver.js
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| ...baseEvent, | ||
| ts: baseTs - 1e5, | ||
| ph: 'I', | ||
| s: 't', |
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i can't find what this "s" is. not seeing it in trace_event source or one of my example traces. you sure about it?
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I see it for all Resource* and TracingStarted* events, but I'm not sure it's necessary. Prefer I remove?
lighthouse-core/lib/asset-saver.js
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| * @param {LH.Gatherer.Simulation.Result['nodeTimings']} nodeTimings | ||
| * @return {LH.Trace} | ||
| */ | ||
| function convertNodeTimingsToTrace(nodeTimings) { |
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I think we should move these fn's into their own file and require into asset-saver
lighthouse-core/lib/asset-saver.js
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| mimeType: record._mimeType, | ||
| encodedDataLength: record._transferSize, | ||
| fromCache: false, | ||
| fromServiceWorker: false, |
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fromServiceWorker: record.fetchedViaServiceWorker
lighthouse-core/lib/asset-saver.js
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| { | ||
| ...baseRequestEvent, | ||
| name: 'ResourceReceiveResponse', | ||
| ts: ts(endTime), |
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wdyt about (startTime + endTime) / 2 instead?? makes for a more attractive visual.
lighthouse-core/lib/asset-saver.js
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| const requestData = {requestId: requestId.toString(), frame}; | ||
| /** @type {Omit<LH.TraceEvent, 'name'|'ts'|'args'>} */ | ||
| const baseRequestEvent = {...baseEvent, ph: 'I', s: 't', dur: 0}; |
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same response :)
lighthouse-core/lib/asset-saver.js
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| * @param {LH.Gatherer.Simulation.NodeTiming} timing | ||
| * @return {LH.TraceEvent[]} | ||
| */ | ||
| function createFakeNetwork(record, timing) { |
lighthouse-core/lib/asset-saver.js
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| * @param {{startTime: number, endTime: number}} timing | ||
| * @return {LH.TraceEvent} | ||
| */ | ||
| function createFakeEvaluateScript(cpuNode, timing) { |
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createFakeEvaluateScriptEvent
patrickhulce
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| // 0ms requests get super-messed up rendering | ||
| // Use 20ms instead so they're still hoverable | ||
| let {startTime, endTime} = timing; // eslint-disable-line prefer-const | ||
| if (startTime === endTime) endTime += 20; |
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I still feel uncomfortable changing the data purely for flamechart UX reasons. E.g. a network request that must start after a previous one finishes won't now. Feels weird, man.
How about... We do know there's pretty high overhead to create a network request. This is something we've discussed, but simulator doesn't acknowledge just yet. Let's add it and say request creation costs ~0.3ms or thereabouts.
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Alright 0.3ms it is 👍
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@patrickhulce can you file an issue for the followups we were talking about? (though you probably already have a branch ready for PR.. :) |
note: test failures blocked on #5377
running the CLI with
--save-assetswill now output the optimistic FCP and pessimistic TTI traces that lantern computed, waaaaaaay easier for debugging and whatnotnext steps I'll add labels for the various opportunities so those are easier to debug as well
the code's a bit big for asset-saver so it might make sense to pull it out, but I'm drawing a blank where it should live, straight in lib? next to simulator? what do we call it?
CNN TTI
CNN FCP