# Synchronization Classes

The UVM provides event and barrier synchronization classes for managing concurrent processes.

- uvm_event#(T) - UVM’s event class augments the SystemVerilog event datatype with such services as setting callbacks and data delivery.
- uvm_barrier - A barrier is used to prevent a pre-configured number of processes from continuing until all have reached a certain point in simulation.
- uvm_event_pool and uvm_barrier_pool - The event and barrier pool classes are specializations of uvm_object_string_pool #(T) used to store collections of ~uvm_event#(uvm_object)~s and uvm_barriers, respectively, indexed by string name. Each pool class contains a static, “global” pool instance for sharing across all processes.
- uvm_event_callback - The event callback is used to create callback objects that may be attached to uvm_event#(T)s.

Summary

Synchronization Classes

> class uvm_event#(
> | type | T | = | uvm_object
> ) extends uvm_event_base

The uvm_event class is an extension of the abstract uvm_event_base class.

> class uvm_barrier extends uvm_object

The uvm_barrier class provides a multiprocess synchronization mechanism.

> class uvm_object_string_pool #(
> | type | T | = | uvm_object
> ) extends uvm_pool #(string,T)

This provides a specialization of the generic uvm_pool #(KEY,T) class for an associative array of uvm_object-based objects indexed by string.

> virtual class uvm_event_callback#(
> | type | T | = | uvm_object
> ) extends uvm_object

The uvm_event_callback class is an abstract class that is used to create callback objects which may be attached to uvm_event#(T)s.