Estimate RAM usage information of an embedded device

I'm monitoring the performance of an ARM-based embedded device which runs poky linux distro (from Yocto project) which contains OpenEmbedded build system. I need to get the MHz (CPU cycles) consumption and the RAM used for any process that runs on the system. Though top utility allows me to see the CPU % used (which allows me to estimate CPU MHz in turn), it just gives the *virtual memory size (VSZ)* used by the process but no *physical memory* used. Is there a way I can get this information I need?