Errors in recorded traces

[wwwillchen]

I've been running some benchmarking analysis for CPU throttling and came across some unusual trace from using Lighthouse to collect traces on an Android Nexus 4 device.

The aggregated statistics (e.g. scripting) shows a negative value. I noticed there were numerous console errors from DevTools when loading these traces.

From caseq:

It looks like it's due to a somewhat malformed trace we get from lighthouse, which is in turn likely due to poor timer resolution on Android combined with LH messing with traces by sorting the events using a non-stable sort.

[wardpeet]

Can this be related to #2336 ?

[wwwillchen]

@wardpeet - I don't think so because I saw it on pretty much every site with Nexus 4 and not all of them had redirects.

[brendankenny]

turns out this isn't Lighthouse messing with the trace, it's speedline messing with the trace :)