Use the Wait Time chart to determine if the Azure SQL Managed instance is experiencing Tempdb contention. Note that Tempdb contention refers to a bottleneck for threads trying to access allocation pages that are in-memory; it has nothing to do with I/O.

The Tempdb Wait Time chart plots wait contention over time for the resource types:

PFS

Page free space

GAM

Global allocation map

SGAM

Shared global allocation map