SCore-D User Manual (1)
a.out [-score option_string] arg1 arg2 ... argn
Here let us assume a.out is an executable file linked with
SCore-D runtime library. When invoking a "SCore-D aware" program,
resulting process on a local host is called Front End Process
(FEP), and the runtime library of FEP tries to connect specified
SCore-D server host and then it forks a parallel process on a
cluster. User code runs in parallel on the cluster. After the
connection with SCore-D is established, all the standard output of the
user parallel program are passes to the FEP and output as the standard
output of the FEP. The standard error is also output as well.
SIGTSTP (^Z) and
fg UNIX shell command) are caught
by the FEP, and SCore-D controls the FEP and corresponding user
parallel process to follow the action required. Thus SCore-D gives an
illusion that FEP is an entity of user's parallel program execution.
During the initialization of the runtime
library, the command argument is scanned, and the library assumes that
the argument next to the keyword -score is SCore option
string. The rest of the arguments are passed to user program,
Options in the option string is separated by comma (,) or blank. When
each option is separated by blanks, entire option string must be
quoted. The -score keyword and the next option string can be
placed anywhere in the command arguments. Each option setting
consists of keyword and value. Like shell einvironment
variable, the keyword and associated value are separated by an equal
(=) symbol character.
Option string is searched from left to right. If there are two or more
options having the same keyword, leftmost one is taken. After
searching the option string, SCore tries to get the other option
strings from shell environment variable named
Effective options can vary depending on which library is linked with
the executable file. In general, communication library and language
runtime library are required to be linked. Such libraries may have
different options from the others. Thus, the options listed in this
section is a minimum set.
SCore takes the value of shell environment variable
environ as a option string. Its format is the same as
the one in command argument. The option string spcified in the
environment variable can contain the default
This option setting is replaced by the environment variable
name and its value. SCore does not pass environment
variables of invoked process to the processes spawned.
The program prints option setting information, and then exits.
The program first prints current option setting, and then
starts its execution.
The number of host nodes required to run the program is
specified by number_of_nodes option. Note that the
specified number is taken as a request, and the actual number
of allocated host number may be different.
The hostname is assumed to be SCore-D server host, and
the runtime library tries to connect to the host to submit a job.
When a user parallel process terminates, SCore-D output some
statistics information on the execution of the parallel process.
In addition to the stat option, statistics
information on individual nodes is also output.
Invoke a real-time activity monitor of a user parallel
process. Currently two monitor programs, loadmonitor
and loadmonitor3d, are available. The
loadmonitor is a simple X-client program and
displays a two dimensional image.
And the loadmonitor3d is a OpenGL (MESA and GLUT)
application and displayes a three dimensional image. By
draggin mouse on the window, user can rotate (left button),
enlarge or shrink (middle button) the image.
On both monitoring programs, red cell or bar indicates busy
node, and blue cell or bar indicates idle node. To use one of
the above monitoring programs, user must set a proper
PATH environment for the program(s).
If the debug
options is specified, and SCore-D detects an exceptional
signal, then SCore-D tries to invoke a GDB and let it attach
to the user program. DISPLAY shell environment
variable is expected to be set properly, so that xterm
under which GDB runs can display a window on your host.
- Termination (Deadlock) Detection
SCore-D monitors activities of user parallel processes. When
SCore-D detects a explicit termination due to a deadlock,
SCore-D kills the terminated user parallel process.
- User program binary file
User program binary files must be readable by SCore-D. This is
because, when a user submit a job to SCore-D, firstly SCore-D
copies user program binary file to SCore-D temporary directory.
- User-ID and Current Working Directory
SCore-D fork() and exec() user programs, and
set user-ID and change current working directory. When users are
using NFS (Network File System) or AFS (Andrew File System), the
PWD environment variable is not set properly under some
shells. In this case SCore-D fails to spawn user processes. To
avoid this, use tcsh or others which set the
PWD environment variable properly. Further, because of
protection, user-ID must be larger than or equal to 100. SCore-D
also fails to spawn user processes, if it has no ROOT
- ENVIRONMENT VARIABLES
Option string specified in the command argument is analyzed,
then the runtime library tries to get option string from this
shell environment variable also.
Next to SCORE_OPTIONS einvironment variable,
this environment variable is analized.
- SEE ALSO
SCore User Manual
Real World Computing Partnership
Parallel Distributed System Software Tsukuba Laboratory
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