In computing, a process is the instance of a computer program that is being executed by one or many threads. It contains the program code and its activity. Depending on the operating system (OS), a process may be made up of multiple threads of execution that execute instructions concurrently
In computer science, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler, which is typically a part of the operating system. The implementation of threads and processes differs between operating systems, but in most cases a thread is a component of a process.
Hands on tools
In general, we use the
top command to view summary information about the running processes and threads (and much more). To see actual thread activity (blech) on an OS X system, type the
sudo dtruss -ap pid (where PID is the process you want to investigate).
There are GUI tools where you can view this information, but you should use command line interface.