Data Cache component
It is common to use IPC for Inter Process Communications, among those is the shared memory capability. In Zend Server Data Cache, we implement MMAP and not IPC for shared memory caching (SHM APIs for Data Cache).
When you run Data Cache API SHM calls to store objects in PHP memory, they do not appear within IPC. To illustrate, use PHP script with 'zend_shm_cache_store('foo','bar');' while monitoring IPC with 'watch ipcs -a'.
Since Zend Server Data Cache is using MMAP, there should be no activity in IPC when using Data Cache APIs.