|Machine type||RISC-based SMP system.|
|Models||AlphaServer GS80, GS160, GS320, GS1280.|
|Operating system||Tru64 Unix (Compaq's flavour of Unix).|
|Connection structure||2-D torus.|
|Compilers||Fortran 77, Fortran 90, HPF, C, C++.|
|Vendors information Web page||http://h18002.www1.hp.com/alphaserver/sc_gs.html|
|Year of introduction||1999.|
|Clock cycle||1.3 GHz|
|Theor. peak performance|
|Per Proc.||2.6 Gflop/s|
|Memory||≤ 512 GB|
|No. of processors||≤ 64|
|Aggregate (global)||1638 GB/s|
We only discuss the largest (fastest) member of the GS family here as the others
do not qualify anymore with respect to the speed boundary we set (80 Gflop/s).
The GS series is a family of ccNUMA servers with currently the fastest
Alpha EV7 processor available at 1.3 GHz, the EV7z. The systems are build with
drawers that house 4 dual-processor cards. A fully configured GS1280 harbours
Since the system is based on the EV7 processor which has four direct communication links on chip with a bandwidth of 6.4 GB/s each, the natural way of linking the processors is in a 2-D torus structure. Practical measurements have shown that the NUMA factor for a 16-processor system is quite low: only 1.6, see .
The EV7 at 1.3 GHz has a Theoretical Peak Performance of 2.6 Gflop/s. Because of its exceptional high memory bandwidth it may be expected to be able to perform well on a large variety of applications showing in a higher overall efficiency even though its peak performance is lower than that of many other processors. The maximum amount of memory is 512 GB, 8 GB/processor, enough to qualify it for high-end technical/scientific applications for the number of processors available.
Because of its ccNUMA character, users can employ OpenMP for shared-memory parallelisation on the GS systems to up to 64 processors in the GS1280. Of course also MPI can be used along with the full range of Compaq compilers.
For the EV7-based GS1280 as yet no meaningful performance results are known.