AIXpert Blog is about the AIX operating system from IBM running on POWER based machines called Power Systems and software related to it like IBM Systems Director, PowerVM for virtualisation and PowerSC for security plus performance monitoring and nmon
I have been wondering why the lower end POWER7 machines have local and far memory and not local and near. Perhaps you wondered too! Well at the Miami Power Technical University, I got to talk to Dr Joel Tendler (IBMer) and a POWER7 processor guru and put the question to him. He covered this sort of architectural topic in his presentation at the event and I learnt a lot in this area by listening to the "master". Below is some background and the explanation too. The POWER7 chips has two memory controllers for maximum performance but... [More]
Finally, I have the types of memory by POWER7 model double checked. I refreshed the table in part 1 but thought I should make sure every one sees the final version so I have not mislead people. Only the Power 770/780 and Power 797 have Near memory. All the smaller machine operate a Local memory meaning on the same same POWER7 chip and Far memory for any access to another POWER7 chip's memory.
On Power6 the largest machine was the Power 595 with 64 Physical CPUs (cores) across eight CPU books in the machine - each CPU book having 4 Power6 chips and so 8 CPUs (Power6 is a dual CPU chip design). However, with Power7 that has stepped up to 256 CPUs across the same eight CPU books with four chips but with 8 CPUs each so that is 32 CPUs per book. I might be stating the obvious but memory access to memory directly attached to the Power chip on which your process is running is slightly faster than memory access via a Power chip near by... [More]