Hi Chris, On Fri, 13 Jan 2012 09:54:20 +1100 Christopher Samuel <sam...@unimelb.edu.au> wrote: > > On 12/01/12 20:34, Christopher Yeoh wrote: > > > Cross Memory Attach (CMA) is a pair of new syscalls > > (process_vm_readv and process_vm_writev) which allow for fast > > intranode communication. It has added to the Linux 3.2 kernel. > > Do you have any figures comparing some code with and without CMA ? >
Here's some benchmarking results I did a while back on a single 64-way (SMT) POWER6 box. HPCC results: ============= MB/s Num Processes Naturally Ordered 4 8 16 32 Base 1235 935 622 419 CMA 4741 3769 1977 703 MB/s Num Processes Randomly Ordered 4 8 16 32 Base 1227 947 638 412 CMA 4666 3682 1978 710 MB/s Num Processes Max Ping Pong 4 8 16 32 Base 2028 1938 1928 1882 CMA 7424 7510 7598 7708 NPB: ==== BT - 12% improvement FT - 15% improvement IS - 30% improvement SP - 34% improvement IMB: === Ping Pong - ~30% improvement Ping Ping - ~120% improvement SendRecv - ~100% improvement Exchange - ~150% improvement Gather(v) - ~20% improvement Scatter(v) - ~20% improvement AlltoAll(v) - 30-50% improvement Regards, Chris -- cy...@ozlabs.org
