Application layers :

• I/O or CPU intensive,  traffic and cpu usage pattern, time change pattern
• service dependencies and strength of connections
• internal optimization: efficiency of buffer utilization, reduce buffer memory copies, user/kernal spaces, async if possible.

IAAS layers

• characteristics of devices: SSD/Spinning HD, Network Band width/QoS,
• capacities : availability of cpu cores, memory, disk space, networks.

Smart scheduler:

•  scheduling based on knowledge provided on both.
• dynamically consolidating/scaling based on current load