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core(lantern): extract main thread events w/o TraceProcessor #16049
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@@ -785,12 +785,102 @@ class PageDependencyGraph { | |
} | ||
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/** | ||
* @param {LH.TraceEvent[]} mainThreadEvents | ||
* Sorts and filters trace events by timestamp and respecting the nesting structure inherent to | ||
* parent/child event relationships. | ||
* | ||
* @param {LH.TraceEvent[]} traceEvents | ||
* @param {(e: LH.TraceEvent) => boolean} filter | ||
*/ | ||
static _filteredTraceSort(traceEvents, filter) { | ||
// create an array of the indices that we want to keep | ||
const indices = []; | ||
for (let srcIndex = 0; srcIndex < traceEvents.length; srcIndex++) { | ||
if (filter(traceEvents[srcIndex])) { | ||
indices.push(srcIndex); | ||
} | ||
} | ||
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// Sort by ascending timestamp first. | ||
indices.sort((indexA, indexB) => traceEvents[indexA].ts - traceEvents[indexB].ts); | ||
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// Now we find groups with equal timestamps and order them by their nesting structure. | ||
for (let i = 0; i < indices.length - 1; i++) { | ||
const ts = traceEvents[indices[i]].ts; | ||
const tsGroupIndices = [i]; | ||
for (let j = i + 1; j < indices.length; j++) { | ||
if (traceEvents[indices[j]].ts !== ts) break; | ||
tsGroupIndices.push(j); | ||
} | ||
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// We didn't find any other events with the same timestamp, just keep going. | ||
if (tsGroupIndices.length === 1) continue; | ||
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// Sort the group by other criteria and replace our index array with it. | ||
const finalIndexOrder = TraceProcessor._sortTimestampEventGroup( | ||
tsGroupIndices, | ||
indices, | ||
i, | ||
traceEvents | ||
); | ||
indices.splice(i, finalIndexOrder.length, ...finalIndexOrder); | ||
// We just sorted this set of identical timestamps, so skip over the rest of the group. | ||
// -1 because we already have i++. | ||
i += tsGroupIndices.length - 1; | ||
} | ||
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// create a new array using the target indices from previous sort step | ||
const sorted = []; | ||
for (let i = 0; i < indices.length; i++) { | ||
sorted.push(traceEvents[indices[i]]); | ||
} | ||
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return sorted; | ||
} | ||
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/** | ||
* @param {LH.Trace} trace | ||
* @param {LH.Artifacts.TraceEngineResult} traceEngineResult | ||
* @return {LH.TraceEvent[]} | ||
*/ | ||
static _collectMainThreadEvents(trace, traceEngineResult) { | ||
const Meta = traceEngineResult.data.Meta; | ||
const rendererPidToTid = new Map(); | ||
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for (const pid of Meta.topLevelRendererIds) { | ||
const threads = Meta.threadsInProcess.get(pid) ?? []; | ||
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let found = false; | ||
for (const [tid, thread] of threads) { | ||
if (thread.args.name === 'CrRendererMain') { | ||
rendererPidToTid.set(pid, tid); | ||
found = true; | ||
break; | ||
} | ||
} | ||
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if (found) continue; | ||
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// `CrRendererMain` can be missing if chrome is launched with the `--single-process` flag. | ||
// In this case, page tasks will be run in the browser thread. | ||
for (const [tid, thread] of threads) { | ||
if (thread.args.name === 'CrBrowserMain') { | ||
rendererPidToTid.set(pid, tid); | ||
found = true; | ||
break; | ||
} | ||
} | ||
} | ||
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return this._filteredTraceSort(trace.traceEvents, e => rendererPidToTid.get(e.pid) === e.tid); | ||
} | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. w/o There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. I don't think it's needed. I looked at how we use main thread events in lantern and we just look for top level CPU tasks. Those should really never have the same timestamp which seems to be the purpose of that function. There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. seems convincing |
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/** | ||
* @param {LH.Trace} trace | ||
* @param {LH.Artifacts.TraceEngineResult} traceEngineResult | ||
* @param {LH.Artifacts.URL} URL | ||
*/ | ||
static async createGraphFromTrace(mainThreadEvents, trace, traceEngineResult, URL) { | ||
static async createGraphFromTrace(trace, traceEngineResult, URL) { | ||
const mainThreadEvents = this._collectMainThreadEvents(trace, traceEngineResult); | ||
const workerThreads = this._findWorkerThreads(trace); | ||
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/** @type {Lantern.NetworkRequest[]} */ | ||
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rendererPidToTid here gets constructed with different results than TraceProcessor was doing ...
consider the first test in core/test/computed/metrics/speed-index-test.js (
should compute a simulated value
) as an example, TraceProcessor only has one renderer in this map, but this version has two. the extra one is the initial about:blank renderer. this seems like something to avoid ... it happens b/c the about:blank is intopLevelRendererIds
. I'm not yet sure how TraceProcessor ends up excluding it.the result is more events end up in mainThreadEvents
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ok I think
const mainFramePids = Meta.mainFrameNavigations.map(nav => nav.pid);
instead of usingtopLevelRendererIds
kinda resolves this. Not sure what would happen w/o any navigation though .... so I'll fall back totopLevelRendererIds
in that case.