A question came up recently about my choice of definitions for “MB” used in the computation of memory bandwidth (in “MB/s”) in the STREAM benchmark. According to this reference from NIST, the convention is: Binary Powers Value abbreviation full name 2^10 1,024 KiB kibibyte 2^20 1,048,576 MiB mebibyte 2^30 1,073,741,824… read more
Some comments on the Xeon Phi coprocessor
As many of you know, the Texas Advanced Computing Center is in the midst of installing “Stampede” — a large supercomputer using both Intel Xeon E5 (“Sandy Bridge”) and Intel Xeon Phi (aka “MIC”, aka “Knights Corner”) processors. In his blog “The Perils of Parallel”, Greg Pfister commented on the… read more
AMD Opteron “Shanghai” and “Istanbul” Local and Remote Memory Latencies
In an earlier post, I documented the local and remote memory latencies for the SunBlade X6420 compute nodes in the TACC Ranger supercomputer, using AMD Opteron “Barcelona” (model 8356) processors running at 2.3 GHz. Similar latency tests were run on other systems based on AMD Opteron processors in the TACC… read more