Compared to Chrome beta (71), we load tripadvisor.ca very slowly. Chrome seems to finish loading in a few seconds, whereas we are taking upwards of 30s to do a full load. We also get a slow running script warning while loading, while Chrome does not run into this. Profiles Without tracking protection: https://perfht.ml/2TeHKnA With tracking protection: https://perfht.ml/2zSDlO1 The profiles were captured on a Moto G5 with GeckoView Example 65.

Here are profiles without remote devtools open: Without tracking protection: https://perfht.ml/2Tuwqnr With tracking protection: The look of the website has changed and I am not always getting a slow script warning; I only received one on the profile with tracking protection this time, whereas in both of the previous profiles that occurred. Without tracking protection: https://perfht.ml/2TxZuKr With tracking protection: https://perfht.ml/2Ty1IJS

Denis Palmiero noted that we're doing a lot of transitions between Interpreter and Baseline in this startup profile. The overhead of these is currently very high but Jan's compiled interpreter should help that situation (as well as other page-load situations) quite a bit. Linking as see-also to bug 1499324.