After building emacs from the master branch (with Org mode version 9.6
release_9.6-81-g563a43) I noticed the org-clock-sum-today function takes
much more time compared to my previous emacs build (with Org mode version
9.5.4 release_9.5.4-19-g4dff42) in a large org buffer.

Are there any settings that could speed up the calculation?

Thank you!
Tijs