This was especially noticed in combination with QueuedTracking where the response time of one tracker request used to be about 4ms. It is now about 20-40ms depending on the server etc. Most of the time is spent in reading the ini config and static container / dependency injection.

I reckon the normal tracker mode got a bit slower as well but as a normal request takes maybe 50-200ms anyway the regression is probably not that much of a problem.

I uploaded a profile here: https://blackfire.io/profiles/983424c0-aa7e-446c-823b-59955f48212f/graph

In this case a client decided to use the QueuedTracking as it was very important to have a very fast tracker response time but the performance regressed.