Solaris threads are implemented as a user-level library, using the kernel's threads of control, that are called light-weight processes (LWPs). In the Solaris environment, a process is a collection of LWPs that share memory. Each LWP has the scheduling priority of a UNIX process and shares the resources of that process. LWPs coordinate their access to the shared memory by using synchronization mechanisms such as locks. An LWP can be thought of as a virtual CPU that executes code or system calls. The threads library schedules threads on a pool of LWPs in the process, in much the same way as the kernel schedules LWPs on a pool of processors. Each LWP is independently dispatched by the kernel, performs independent system calls, incurs independent page faults, and runs in parallel on a multiprocessor system. The LWPs are scheduled by the kernel onto the available CPU resources according to their scheduling class and priority.