I know that VarDumper in the profiler brings lot of improvements especially when displaying objects but it's a bit weird to loose so much performance on some pages when upgrading to Symfony 3.3.

In fact the more important impact is linked to pages that are composed with render controller. Exceution time and memory usage increases a lot. Please check the benchmark file in attachment.

Benchmark-20170620.pdf

To resume (each widget is integrated to a dashboard as render controller):
In PHP 5.6.30:

• Dashboard with 12 widgets: SF 3.1.5: 978ms - SF 3.3.2: 2499ms -> +255%
• Dashboard Global with 14 widgets: SF 3.1.5: 1430ms - SF 3.3.2: 3307ms -> +231%

In PHP 5.6.30:

• Dashboard with 12 widgets: SF 3.1.5: 406ms - SF 3.3.2: 861ms -> +212%
• Dashboard Global with 14 widgets: SF 3.1.5: 748ms - SF 3.3.2: 1338ms -> +179%

I know some work have been done to improve the performance here: #19986

I'm not sure if something can be done, especially for render controller use case, because the profiling is done for all sub requests even if a lot of data comes from the Master Request (Doctrine, Security, Twig, etc). I just don't understand why the memory usage increase as much. Please also note that the Dashboard page doesn't contains any form. It seems the Routing page of sub requests make the memory increase a lot.

I let you close the ticket if you think that nothing can be done.