An Efficient Search Algorithm of Worst-Case Cache Flush Timings

Abstract

In recent years, the use of cache memory has been desired

A Simulation-Based Analysis for Worst Case Delay of Single and Multiple Interruptions

“…8), the equation (1) can be rewritten as follows because τ (k l , k l+1 + 1) is independent from any other τ (k l , k l +1 + 1).…”

“…Then Lee, et al 7) pointed out the importance of the effect on caches, and proposed an analytical method to bound cache miss penalty due to interruptions. This approach was extended in two directions; to incorporate the cache pollution by preemptors 12), 14) ; and to analyze more accurately using memory access trace obtained from the simulation or instrumented execution of a workload 8) . Although each of those work above has its own good feature, e.g., applicable without running 3),4) , efficiently handling multiple interruptions and/or preemptors 7),8),12), 14) , they commonly have the problem on accuracy.…”

An Efficient Analysis of Worst Case Flush Timings for Branch Predictors

“…While this approach should be too natural and trivial for typical WCET problems, it is still challenging for the preemption delay problem because we have a huge search space from which we have to find out the worst-case preemption points. In the first proposal using this approach, Miyamoto, et al 15) used it to find the worst case flush timings (WCFT) of direct-map caches for a process preempted F times. That is, WCFT is the set of preemption timings that maximizes the total cache misses in the execution of the process.…”

“…Their more recent report 14) showed a better algorithm whose time complexity is O(NF ) if we assume the average gap between two accesses to a cache block is a constant independent of N . This improvement is based on the fact that the effect of an access to a directmap cache is nullified by the following access to the same cache block because what resides in the block is determined only by the second access regardless of the first one.…”

“…First we show that a dynamic programming technique, which solved the WCFT problem of caches 15) , is also applicable to the problem for bimodal predictors to obtain an O(N 2 F ) algorithm. Secondly and more importantly, we improve the algorithm to achieve O(NF ) time complexity in a practical sense and exhibit its efficiency through our evaluation with SPEC CPU95 benchmarks.…”