Smart Cache

About: Smart Cache is a research topic. Over the lifetime, 7680 publications have been published within this topic receiving 180618 citations.

Reverse Engineering Intel Last-Level Cache Complex Addressing Using Performance Counters

Abstract: Cache attacks, which exploit differences in timing to perform covert or side channels, are now well understood. Recent works leverage the last level cache to perform cache attacks across cores. This cache is split in slices, with one slice per core. While predicting the slices used by an address is simple in older processors, recent processors are using an undocumented technique called complex addressing. This renders some attacks more difficult and makes other attacks impossible, because of the loss of precision in the prediction of cache collisions. In this paper, we build an automatic and generic method for reverse engineering Intel's last-level cache complex addressing, consequently rendering the class of cache attacks highly practical. Our method relies on CPU hardware performance counters to determine the cache slice an address is mapped to. We show that our method gives a more precise description of the complex addressing function than previous work. We validated our method by reversing the complex addressing functions on a diverse set of Intel processors. This set encompasses Sandy Bridge, Ivy Bridge and Haswell micro-architectures, with different number of cores, for mobile and server ranges of processors. We show the correctness of our function by building a covert channel. Finally, we discuss how other attacks benefit from knowing the complex addressing of a cache, such as sandboxed rowhammer.

Cache defeat detection and caching of content addressed by identifiers intended to defeat cache

Abstract: Systems and methods for cache defeat detection are disclosed. Moreover, systems and methods for caching of content addressed by identifiers intended to defeat cache are further disclosed. In one aspect, embodiments of the present disclosure include a method, which may be implemented on a system, of resource management in a wireless network by caching content on a mobile device. The method can include detecting a data request to a content source for which content received is stored as cache elements in a local cache on the mobile device, determining, from an identifier of the data request, that a cache defeating mechanism is used by the content source, and/or retrieving content from the cache elements in the local cache to respond to the data request.

System and method for smart persistent cache

Abstract: A system and method for smart, persistent cache management of received content within a terminal. Received content is tagged with cache directive allowing cache control to determine which of cache storage locations to use for storage of content. Cache control detects the number of instances that received content correlates to a newer version of purged content and provides the ability to re-classify cache persistence directive based upon the number of instances.

Storing cache metadata separately from integrated circuit containing cache controller

Abstract: A technique includes using a cache controller of an integrated circuit to control a cache including cached data content and associated cache metadata. The technique includes storing the metadata and the cached data content off of the integrated circuit and organizing the storage of the metadata relative to the cached data content such that a bus operation initiated by the cache controller to target the cached data content also targets the associated metadata.

Improving Cache Management Policies Using Dynamic Reuse Distances

Abstract: Cache management policies such as replacement, bypass, or shared cache partitioning have been relying on data reuse behavior to predict the future. This paper proposes a new way to use dynamic reuse distances to further improve such policies. A new replacement policy is proposed which prevents replacing a cache line until a certain number of accesses to its cache set, called a Protecting Distance (PD). The policy protects a cache line long enough for it to be reused, but not beyond that to avoid cache pollution. This can be combined with a bypass mechanism that also relies on dynamic reuse analysis to bypass lines with less expected reuse. A miss fetch is bypassed if there are no unprotected lines. A hit rate model based on dynamic reuse history is proposed and the PD that maximizes the hit rate is dynamically computed. The PD is recomputed periodically to track a program's memory access behavior and phases. Next, a new multi-core cache partitioning policy is proposed using the concept of protection. It manages lifetimes of lines from different cores (threads) in such a way that the overall hit rate is maximized. The average per-thread lifetime is reduced by decreasing the thread's PD. The single-core PD-based replacement policy with bypass achieves an average speedup of 4.2% over the DIP policy, while the average speedups over DIP are 1.5% for dynamic RRIP (DRRIP) and 1.6% for sampling dead-block prediction (SDP). The 16-core PD-based partitioning policy improves the average weighted IPC by 5.2%, throughput by 6.4% and fairness by 9.9% over thread-aware DRRIP (TA-DRRIP). The required hardware is evaluated and the overhead is shown to be manageable.