This has been a busy week. A lot of fixes have landed, setting up the Firefox 57 cycle for a good start. On the platform side, a notable change that will be in the upcoming Nightly is the fix for document.cookie using synchronous IPC. This super popular API call slows down various web pages today in Firefox, and starting from tomorrow, the affected pages should experience a great speedup. I have sometimes seen the slowdown caused by this one issue to amount to a second or more in some situations, thanks a lot to Amy and Josh for their hard work on this feature. The readers of these newsletters know that the work on fixing this issue has gone on for a long time, and it's great to see it land early in the cycle.

On the front-end side, more and more of the UI changes of Photon are landing in Nightly. One of the overall changes that I have seen is that the interface is starting to feel a lot more responsive and snappy than it was around this time last year. This is due to many different details. A lot of work has gone into fixing rough edges in the performance of the existing code, some of which I have covered but most of which is under the Photon Performance project. Also the new UI is built with performance in mind, so for example where animations are used, they use the compositor and don't run on the main thread. All of the pieces of this performance puzzle are nicely coming to fit in together, and it is great to see that this hard work is paying off.

On the Speedometer front, things are progressing with fast pace. We have been fixing issues that have been on our list from the previous findings, which has somewhat slowed down the pace of finding new issues to work on. Although the SpiderMonkey team haven't waited around and are continually finding new optimization opportunities out of further investigations. There is still more work to be done there!

I will now move own to acknowledge the great work of all of those who helped make Firefox faster last week. I hope I am not mistakenly forgetting any names here!