What makes Elixir Processes Lightweight?

Elixir is based on Erlang and is built to cater to applications on distributed systems. Elixir already has features like Open Telecom Platform (OTP) and behaviors like Supervisors and GenServer that reduces the hassle of programming scheduler and concurrency control. Hence, making multiprocessing a breeze in Elixir.

As much as processes sound similar to the processes of the Operating System, they are very much different. Processes in OS are heavy in terms of state storage and thus are very time-consuming. Moreover, OS-level multiprocessing has a lot of complex rules to access and store bits. This adds even more weight to the processes. Since most programming languages perform multiprocessing at the OS level, their processes are heavyweight.

Elixir, on the other hand, has very lightweight processes. Elixir is built on Erlang, which has BEAM as an underlying virtual machine. One of the important features of BEAM is that it runs in a single OS process. Each elixir process is created, scheduled, and managed in the VM itself without any intervention from the OS. Moreover, since the processes are not in direct contact with the Kernel, the hardware-related safety instructions are omitted for elixir multi-processing.

All Elixir processes run in an isolated environment, and there is no concept of shared memory among processes in Elixir. It reduces the task of implementing synchronization on the user’s end. The way processes communicate with each other is by asynchronous message-passing.

All processes have a mailbox where they get messages, After receiving the message, the process performs pattern matching on the received message and carries the operations accordingly. To send a message to any process x, process y only needs the process ID (PID) of x.

Processes in Elixir are immutable and hence stateless. Stack and recursion are used to store the state of the process during multiprocessing. BEAM act as the scheduler and schedules process. If a process is dead, the Supervisor detects it and starts a new process, thus ensuring fault tolerance.

All these features of Elixir help create lightweight processes and support easy concurrency and system scalability.