Refer to Bug 1264535 comment#7 https://cleopatra.io/#report=9cc2bcb2eaa3d81d9d70345b6365c3cd2298e0b2&filter=%5B%7B%22type%22%3A%22RangeSampleFilter%22,%22start%22%3A42807,%22end%22%3A68148%7D,%7B%22type%22%3A%22RangeSampleFilter%22,%22start%22%3A60977,%22end%22%3A67601%7D%5D&selection=0,1,11 From Gecko Profiling data, the Range [43041, 53108]: 9939 100% Startup::XRE_Main 3217 32.4% ├─ Timer::Fire 2013 20.3% ├─ nsInputStreamPump::OnInputStreamReady 1771 17.8% │ ├─ nsInputStreamPump::OnStateStop 157 1.6% │ ├─ nsInputStreamPump::OnStateTransfer 85 0.9% │ └─ nsInputStreamPump::OnStateStart 1482 14.9% ├─ nsRefreshDriver::Tick 614 6.2% │ ├─ PresShell::Paint 341 3.4% │ ├─ PresShell::Flush (Flush_Style) 260 2.6% │ ├─ js::GCRuntime::collect 183 1.8% │ ├─ PresShell::Flush (Flush_InterruptibleLayout) │ └─ ...so on 1217 12.2% ├─ nsHtml5TreeOpExecutor::RunFlushLoop 1050 10.6% │ ├─ nsJSUtils::EvaluateString 148 1.5% │ ├─ EventDispatcher::Dispatch │ └─ ...so on └─ ...so on

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