Shared memory multiprocessors are frequently used as compute servers with multiple parallel programs executing at the same time. In such environments, an operating system switches the contexts of multiple processes. When the operating system switches the contexts, in addition to the cost of saving the context of the processors also can be affected. The blocked algorithm improves cache memory. If frequent context switching replaces the block before it is completely reused, the cache locality in a blocked program cannot be successfully exploited. To address this problem, we propose a preemption-safe policy to utilize the cache locality of blocked programs in a multiprogrammed system, The proposed policy delays context switching until a block is fully reused within a program, but also compensates for the monopolized processor time on processor scheduling mechanisms, Our simulation results show that in a situation where blocked programs are run on multiprogrammed shared-memory multiprocessors, the proposed policy improves the performance of these programs due to a decrease in cache misses. In such situations, it also has a beneficial impact on the overall system performance due to the enhanced processor utilization.