Multiprocessor Considerations

Multiprocessor Considerations

Prior to IRIX 5.3, the kernel BSD framework code and TCP/IP protocol stack executed under a single kernel lock, creating a single-threaded implementation. Beginning with IRIX 5.3, the BSD framework and TCP/IP protocol suite have been multi-threaded to support symmetric multiprocessing. The code uses different kernel locks to protect different critical sections.

IRIX now supports multiple, concurrent threads of execution within the TCP/UDP/IP protocol suite, and the kernel socket layer. In addition, network device drivers run on any available CPU, concurrently with the network software, applications, and other drivers.

This means that any ifnet-based network driver must be prepared to run asynchronously and concurrently with other drivers and with the protocol stack.

Ineffective spl() Functions
Multiprocessor Locking Macros
Compilation Flags for MP TCP/IP
Mutual Exclusion Macros