BANK CONFLICT

bank conflict (n.) A bank "busy-wait" situation. Memory chip speeds are relatively slow when required to deliver a single word, so supercomputer memories are placed in a large number of independent banks (usually a power of 2). A vector of data laid out contiguously in memory with one component per successive bank, can be accessed at one word per cycle (despite the intrinsic slowness of the chips) through the use of pipelined delivery of vector-component words at high bandwidth. When the number of banks is a power of two, then vectors requiring strides of a power of 2 can run into a bank conflict.