The Latches chart shows statistics on Latch requests. A Latch is like a mini-lock that is used internally by SQL Server to serialize access to certain resources. Latches do not participate in transactions and are typically held for a very short duration.
The Latches chart shows the following:
Latch Waits/sec
How many waits for latches occurred per second.
Total Wait Time (ms)
The total amount of time that latch requests spent waiting during the last second, measured in milliseconds.