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Local, Near, Far part 12 - I have a 10 core POWER7 chip, eh!
Time to correct a few assumptions and statements that I made a while back. Previously I said the POWER Hypervisor decides where to put a Virtual Machine (VM/LPAR) based on the Virtual Processor number (spreading factor). Well, apart from it nearly being right ... I was actually wrong! I got talking to one of these very impressive Hypervisor developers in Germany and he put me right. In most of my larger machines, I do what I think is fairly normal for creating an VM - like working with a CPU core to RAM ratio that my customers use, like 1... [More]
Tags: power7 affinity cores chips lssrad core cpu aix srad |
Local, Near & Far Memory part 4 - Aggressive Intelligent Threads
This is a follow on from yesterdays blog due to Chris Gibson highlighting a question/concern from one of his customers in Australia.They were comparing Power6 and Power7 and the utilisation numbers from the SMT Logical Processors and the graphs look different. I looked at some nmon data (what else!) and yes they are looking different and then I ran a simple generated workload test and duplicated the graphs. Below I then explain them - once again these are my personal observations rather than an official AIX developers insider statement. I... [More]
Tags: smt core powervm aix logical threads aggressive vp processor intelligent power7 power |
Local, Near & Far Memory part 3 - Scheduling processes to SMT & Virtual Processors
Before we look further in to memory affinity we need to recap on the scheduling of processes and process threads of a multi-threaded process to simultaneous multi-threading (SMT) processors like POWER7. POWER5 and POWER6 had two modes of SMT off (one thread) and on (two threads) - with SMT=on two processes run at the same time (in the same clock cycle) on the CPU-core but using the different logical units inside of the CPU-core (units like the integer maths (there is more than one), floating point maths (there is more than one), compare and... [More]
Tags: logical core powervm vp aix smt power7 processor power |
