Interprocess Communication Cases

• L4 micro kernel

• LRPC

• ChCore

• Binder

L4 Microkernel Family

L4, like its predecessor microkernel L3, was created by German computer scientist Jochen Liedtke as a response to the poor performance of earlier microkernel-based OSes. Liedtke felt that a system designed from the start for high performance, rather than other goals, could produce a microkernel of practical use.

Message Passing

L4 classifies messages into two categories: short and long. Each category is handled differently in order to reduce the need for copy operations and improve communication performance.

Short Messages

• Use registers to pass messages and enable zero-copy communication. One register is dedicated to storing the message, which remains preserved during context switching.

• Shortcomings: Relies heavily on the underlying hardware architecture.

• Pistachio introduces the concept of a virtual message register. The kernel will map this virtual message register to a physical register or allocate memory space if there are not enough registers available.

Long Messages: