Raptor sometimes displays negative values intermittently for metrics produced during the device reboot test. Most likely this is caused by the inability of the Flame to persist its time across reboots. We've tried to work around this problem in the past using the DEVICETIME environment variable in Raptor, which captures the $EPOCHREALTIME prior to rebooting the device. If this value is off, or if the device hasn't corrected its time by the time any of the performance markers are hit, they will generate metrics that are too small, hence causing negative values. Until bug 1110010 is resolved, I'm not sure we can work around this in a meaningful way, so the point of this bug may just be to throw out metrics that produce negative values.

Ran the restart-b2g test several times, no negative values but still some very small invalid ones (see fullyLoaded Min below). Do you want to set a higher threshold above zero for this workaround? Or is this acceptable for now? Metric Mean Median Min Max StdDev p95 -------------------------------- --------- --------- --------- --------- -------- --------- restartb2g.navigationLoaded 13885.173 13771.350 13317.802 15978.476 483.727 14518.183 restartb2g.navigationInteractive 13886.439 13773.350 13318.802 15979.476 483.702 14519.183 restartb2g.contentInteractive 17464.939 17324.674 16845.327 19695.476 530.502 18291.183 restartb2g.fullyLoaded 16425.900 17875.655 18.501 18386.788 4950.641 18359.706

I think setting the threshold higher will cause some unintended consequences in the future. For example, when using performance.measure(), it would be possible to produce very small results, and these would get tossed. I'd like to say this is acceptable for now; we should never be visualizing negative values for our purposes.

Comment on attachment 8623793 [details] Link to Github pull-request: https://github.com/mozilla-b2g/gaia/pull/30631 Ok, fine with me, as it's just a temporary work-around anyway.

In master: https://github.com/mozilla-b2g/gaia/commit/be75625dda4a6d8e5191174267ea88cab7356d16