Change the zero out strategy for the shared memory. Do not zero out all the shared...

Change the zero out strategy for the shared memory.  Do not zero out all the shared memory at a time.  Each core will zero out the share memory chunk allocated to it when it gets the chunk from the master core.  Therefore the zero out process is parallelized.  Also do not zero out the whole chunk, instead, zero out only 4KB at a time when necessary so that there will not be much flush of L2 cache.