I would like to take some time to describe how to write a high performance file system that is optimized. For simplicity sake, I call it the Write File System and it has 3 goals:

Three Goals of A Write File System

1) USER APPLICATION

We do not want any kernel code. Why? Because it makes it much easier to port to a new platform, both for hardware and operating system reasons. In addition, user code is more reliable. That is, errors that don’t crash the system and just result in a core dump.

In my last blog post, I described the SMP problem.  How adding cpus to an SMP system does not necessarily reliably increase performance.

Pyramid Technology solved this problem by decreasing the granularity of the lock.  This means that the amount of real estate that was controlled by the lock, was decreased.  Thus instead of a single lock for the entire kernel, multiple locks were added for the kernel.  That is, locks were added for each major data structure: Process Table, Schedular, File Systems, etc.