An Efficient Pointer Swizzling Method for Navigation Intensive Applications

Abstract

In this paper we introduce the notion of reservation and residency in the context of object faulting and describe the pointer swizzling method employed in our implementation of a persistent C language P8L. Although the method does not assume any special hardware support, our experiments indicate that the reservation checking method is efficient enough that the addition of reservation checks does not severely compromise the performance in navigation intensive applications. Navigation performance is maintained by reducing the frequency of reservation checks and by replacing each persistent reference with a surrogate upon object fault. The replacement condenses a long persistent identifier down to the size of a virtual memory pointer. The virtual memory requirement of our scheme is modest compared to pointer swizzling at page fault tirne[l]. In one of the test cases, our software based scheme outperformed the hardware based scheme. Compared to pointer swizzling upon discovery as is implemented in [2], our implementation runs about 4 to 10 times faster in terms of pure in-memory navigation.