| Machine type | RISC-based ccNUMA system. |
|---|---|
| Models | Altix 3300, Altix 3700. |
| Operating system | Linux. |
| Connection structure | Crossbar, hypercube (see remarks) |
| Compilers | Fortran 95, C, C++. |
| Vendors information Web page | www.sgi.com/altix/ |
| Year of introduction | 2003. |
System parameters:
| Model | Origin 3700 |
|---|---|
| Clock cycle | 1.5 GHz |
| Theor. peak performance | |
| Per proc. (64-bits) | 6 Gflop/s |
| Maximum (64-bits) | 384 Gflop/s |
| Main memory | |
| Memory/maximal | <= 512 GB |
| No. of processors | 4-64 |
| Communication bandwidth | |
| Point-to-point | 1.6 GB/s |
| Aggregate peak | 44.8 GB/s |
Remarks:
The structure of the Altix 3700 is very similar to that of the SGI Origin systems (see the SGI Origin). The smaller variant of the system, the Altix 3300 is not discussed here. Like the Origin systems the Altix has so-called C-bricks that contains boards with four Itanium 2 processors, 2 memory modules, two I/O ports, and two ASICs called SHUBs. Each SHUB connects to a memory module, an I/O port, and a shared path to two processors. In addition the 2 SHUBs are connected to each other by 6.4 GB/s link. The bandwidth of the memory modules and the I/O ports to the SHUbs are 10.2 and 2.4 GB/s, respectively. For the connection to the other bricks the same routers and network as in the Origin 3000 systems are used: the so-called Numalink3 network with a bi-section bandwidth of 25.6 GB/s. Like the Origin, the Altix is a ccNUMA system which means that the address space is shared between all processors (although it is physically distributed and therefore not uniformly accessible). Note that the bandwidth within the nodes is higher than for the off-board connections. On the boards the new Numalink4 technology is employed.
SGI does not provide its own suite of compilers. Rather it distributes the Intel compilers for the Itanium processors. Also the operating system is Linux and not IRIX, SGI's own Unix flavour. SGI is developing its cluster file system CXFS to run on Linux and will be available shortly.
The 64-processor frames can again be coupled with Numalink3 connections, making them effectively a cluster of Altix systems. However, Numalink allows remote addressing. Therefore, apart from MPI one can also employ the Cray-style shmem library for one-sided communication. It is expected that in the not too remote future also full shared-memory codes with OpenMP could be run on such clusters.
Measured Performances:
No measured performances have been officially reported for this machine yet.