Green (Origin 3800)
Origin 3800 machine has been named Green in honour of the English mathematician
and miller George Green (1793-1841).
|The system has 512 MIPS
processors, each clocked at 400 MHz
and each capable of a peak performance of 800 Megaflops. The machine
uses SGI's NUMAlink interconnect to provide very low latency,
high bandwidth communication between the processors and the 512
Gigabytes of globally shared memory. The system has some local
disk for temporary storage as well as access to the storage area
network (SAN). 504 processors and 504 Gigabytes of memory are
available to applications, and this resource can all be used for
a single job. Note that Green is a batch only system and all jobs
must be submitted from Wren, the Origin 300 machine.
|Aspect of the system
||512 x 400 MHz MIPS R12000 processors
||512 GBytes memory
||Each processor has 8MB Level
2 cache, 32 KB Level 1 data
cache, 32 KB Level 1 instruction cache
||SGI NUMAlink providing sub-microsecond hardware latency, 3-5
latency, sub-microsecond latency for one-sided communications, 6.4GB/s
aggregate bandwidth per brick (4 CPUs).
||This machine is a 512 processor single system image (SSI)
|Maximum job size
||504 processors can be used for a single run
|Theoretical peak performance
||400 Gigaflops - 512 processors x theoretical peak of 800 Megaflops
Green is configured with 4 processors set aside for
operating system tasks, 4 processors for interactive access for system
administrators and other monitoring tasks by the application support
team, and the remaining 504 processors available for batch work. There
is no facility for direct interactive access to this machine.
Green is visible to the outside world as
and therefore it is possible to make use of applications which use the
X windowing system provided that the DISPLAY environment variable is
set to the appropriate value in your batch submission script and you
have allowed access to your local machine (i.e. your local firewall
allows incoming X traffic and you have used the xhost command to give
access permissions to green).