6.3 Summary

Buffer management is used to allocate, manipulate, and free buffers in the system. The basic premise is to minimize data copying. Local and global buffer pools can be used as well as multiple buffer pools each with its own buffer size. A two-level hierarchy, as in the mbuf scheme, and a three-level hierarchy as in the STREAMS scheme are both popular. An typical buffer management scheme can use control blocks to anchor the configuration, status, and statistics information for the message and data blocks.

Timer Management can be implemented using a system tick from the RTOS. It can be implemented per task or via one single task called the Timer Management Task. The differential timer scheme helps avoid the overhead of linked list traversal in decrementing timer counts. Timer block memory requirements are to be analyzed for efficient system design.