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The Sun Fire E25K.

Machine type RISC-based shared-memory multi-processor
Models Fire E25K
Operating system Solaris (Sun's Unix flavour)
Connection structure Crossbar (see remarks)
Compilers Fortran 77, Fortran 90, C, C++
Vendors information Web page
Year of introduction 2004.

System parameters:

Model Fire E25K
Clock cycle 1.2 GHz
Theor. peak performance
Per proc. (64-bit) 4.8 Gflop/s
Maximal (64-bit) 345.6 Gflop/s
Main memory ≤ 576 GB
Number of processors ≤ 72
Communication bandwidth
Aggregate <= 172.8 GB/s


In the E25K is the successor of the 3800-15K system. It employs the newest UltraSPARC IV processors at a clock frequency of 1.2 GHz. The structure of the systems is exactly the same as for its predecessor. In fact, the backplane is identical and one can turn one system into the other by just exchanging the processor boards. The processor/memory boards are plugged into a backplane that is an 18×18 flat crossbar. Each board contains four 1.2 GHz UltraSPARC IV processors and a maximum of 32 GB of memory. So, normally the maximum number of processors would 72. Where in the 3800-15K there is the possibility to use slots of an additional crossbar to plug in extra 2-CPU boards to extend the computational power at the cost of I/O capacity, this possibility is not offered for th3 E25K system. Because of the flat crossbar memory access is uniform and the aggregate bandwidth of the crossbar is 172.8 GB/s. This is equivalent to 2.4 GB/s/processor or 2 B/cycle. So, an 8-byte operand needs 4 cycles to be shipped to the processor.

The main (almost only) difference with its predecessor is that the E25K system employs the dual-core UltraSPARC IV processors. This formally doubles the peak performance per processor, although because of bandwidth constraints the effective performance increase will be lower. Sun maintains a somewhat confusing terminology with respect to multi-threading: it uses the term to express the fact that the two processor cores on an UltraSPARC IV chip each do their processing independently. It calls this chip multi-threading (CMT). Yet the cores are not capable of switching between process threads as what is normally understood by multi-threading.
The E25K is a typical SMP machine with provisions for shared-memory parallelism with OpenMP over the full range of processors in the system.

Measured Performances:
In [42] a speed of 891.4 Gflop/s is reported for a 7-way cluster with a total of 672 processors in solving a dense linear system of unspecified size. The efficiency for this problem is 74%.

next up previous contents
Next: The Unisys Server ES7000. Up: Recount of (almost) available ... Previous: The SGI Origin3900.

Aad van der Steen
Wed Oct 13 15:36:20 CEST 2004