HPC consultant Wolfgang Gentzsch has thoughtfully updated the case of multicore architectures in the HPC context. Over on LinkedIn, via one of the HPC discussion groups, I responded with:

I also enjoyed your article, Wolfgang – thank you. Notwithstanding the drive towards cluster-on-a-chip architectures, HPC customers will require workload managers (WLMs) that interface effectively and efficiently with O/S-level features/functionalities (e.g., MCOPt Multicore Manager from eXludus for Linux, to re-state your example). To me, this is a need well evidenced in the past: For example, various WLMs were tightly integrated with IRIX’s cpuset functionality (http://www.sgi.com/products/software/irix/releases/irix658.html) to allow for topology-aware scheduling in this NUMA-based offering from SGI. In present and future multicore contexts, the appetite for petascale and exascale computing will drive the need for such WLM-O/S integrations. In addition to the multicore paradigm, what makes ‘this’ future particularly interesting, is that some of these multicore architectures will exist in a hybrid (CPU/GPU) cloud – a cloud that may compliment in-house resources via some bursting capability (e.g., Bright’s cloud bursting, http://www.brightcomputing.com/Linux-Cluster-Cloud-Bursting.php). As you also well indicated in your article, it is incumbent upon all stakeholders to ensure that this future is a friendly as possible (e.g., for developers and users). To update a phrase originally spun by Herb Sutter (http://www.gotw.ca/publications/concurrency-ddj.htm) in the multicore context, not only is the free lunch over, its getting tougher to find and ingest lunches you’re willing to pay for!

We certainly live in interesting times!