Recent integration of the cache-partition model has ushered in new paradigms of research in the predictability and schedulability analysis for real-time systems. However, simplicity in the analysis framework has prompted existing contributions to be biased towards a static cache-partitioning scheme. The dynamic scheme has largely been untackled despite its proficiency in schedulability, flexibility, and energy-efficiency. In this letter, we address the latter problem and make initial contributions to a dynamic cache-partition schedulability analysis for multicore partitioned scheduling of real-time fixed-priority sporadic tasks. We devise a sufficient schedulability test and then refine the upper-bound by proposing techniques to reduce the pessimism in the interference caused by cache-contention.