Providing task isolation via TLB coloring

—The translation look aside buffer (TLB) improves the performance of systems by caching the virtual page to physical frame mapping. But TLBs present a source of unpredictability for real-time systems. Standard heap allocated regions do not provide guarantees on the TLB set that will hold a particular page translation. This unpredictability can lead to TLB misses with a penalty of up to thousands of cycles and consequently intra- and inter-task interference resulting in loose bounds on the worst case execution time (WCET) and TLB-related preemption delay. In this work, we design and implement a new heap allocator that guarantees the TLB set, which will hold a particular page translation on a uniprocessor of a contemporary architecture. The allocator is based on the concept of page coloring, a software TLB partitioning method. Virtual pages are colored such that two pages of different color cannot map to the same TLB set. Our experimental evaluations confirm the unpredictability assoc...

• Type: Journal
• Year: 2015
• Where: RTAS
• Authors: Shrinivas Anand Panchamukhi, Frank Mueller
• Keywords: Embedded Systems, RTAS 2015