Lightweight Dynamic Partitioning for Last Level Cache of Multicore Processor on Real System

As multi-core/many-core becomes the trend of processor architecture, conflict in shared cache has become more and more serious that restricts performance improvement of parallel program. Recent research has employed page coloring mechanism to realizing cache partitioning on real system for the purpose of decline shared cache conflict. However, page coloring-based cache partitioning has some side-effects, one is page coloring restricts memory space an application can allocate from which may lead to memory pressure, another is changing cache partition dynamically need massive page copying which will incur large overhead and may go against with application´s performance. To make page coloring based cache partition more practical, we proposed a malloc allocator based dynamic cache partitioning mechanism with page coloring. Memory allocated by our malloc allocator can be partitioned among different applications according to the cache partitioning policy. Our partition policy is based on a type recognition approach. Cache partition can be adjusted at run-time by changing the color of the pages allocated by the malloc allocator. Only coloring the dynamic allocated pages can remission memory pressure and reduce page copying overhead lead by re-coloring compared to all-page coloring. To further alleviate the overhead, we introduced minimum distance page copying strategy and lazy flush strategy. These policies yield performance improvements for co-running applications as high as 14.28% through cache partitioning and reduce the overhead of re-coloring by 55% on average when partitioning frequency is high. Our results demonstrate that only partitioning the dynamically allocated memory can reach the purpose of reducing cache conflict miss and the minimum distance page copying strategy is more beneficial to application with larger data-set and shorter data reuse distance.