lamssi(7)							 LAM SSI OVERVIEW							 lamssi(7)

NAME

       lamssi - introduction to LAM System Services Interface (SSI)

DESCRIPTION

       The SSI in LAM/MPI is used to select one (or more) system services interfaces at run-time.

OVERVIEW

       LAM SSI instances are uniquely described in terms of "kinds" (also referred to as "types") and "modules".

       The  "kind"  refers  to which set of system services the SSI instance will apply to.  For example, LAM currently has several kinds: "boot",
       "coll", "cr" and "rpi".	The "module" refers to a specific SSI instance of a given kind.  Each kind has o

       boot modules are used to start the LAM run-time environment (i.e., they provide the back-end functionality to  lamboot(1)).   boot  modules
       are discussed further in the lamssi_boot(7) man page.

       coll  modules  provide  back-end  algorithms  and  functionality  for  the  MPI	collective  communications.  coll modules are described in
       lamssi_coll(7).

       cr modules provide checkpoint/restart functionality for MPI jobs.  See lamssi_cr(7) for details.

       rpi modules provide back-end functionality for MPI point-to-point communications.  rpi modules are detailed in lamssi_rpi(7).

VERBOSE OPERATION

       The user can force SSI modules to be verbose by setting the LAM_SSI_ssi_verbose environment variable before invoking mpirun,  or  by  using
       the -ssi command line switch to mpirun.	For example:

       mpirun -ssi ssi_verbose 1 C foo
	   Tell the SSI modules to be verbose, and default to sending their output to stderr.

       The  ssi_verbose  kind  is  a "pseudo-kind" in that it is used to pass parameters to the main SSI meta-glue itself -- not to any particular
       kind.  It can take many different parameters to format where and how the verbose output will be sent (note that at least one parameter must
       be  specified, even if it is an invalid parameter).  Any combination of the following parameters may follow the ssi_verbose kind (separated
       by commas):

       syslog
	   Send the verbose output to the syslog.

       syslogpri:<priority>
	   Set the syslog output priority to <priority>.  Using this paramter  implies	the  syslog  parameter.   The  default	priority  is  info
	   (LOG_INFO).	Valid <priority> values are: notice (LOG_NOTICE), info, and debug (LOG_DEBUG).

       syslogid:<id>
	   Use the ID <id> for the syslog prefix.

       stdout
	   Send the verbose output to stdout.

       stderr
	   Send the verbose output to stderr.

       file[:<filename>]
	   Send the verbose output to a file in the LAM per-user, per-node meta information directory (usually located in /tmp).  If <filename> is
	   specified, send the output to the file named lam-<filename>.  If <filename> is not specified, send the output to the  file  named  lam-
	   ssi.txt.

       fileappend
	   Append to the file when sending the verbose output (create the file if it does not exist).  If this parameter is not given, if the file
	   already exists, it will be overwritten.  Using this parameter implies the file parameter.

       level:vlevel
	   Indicate the specific verbosity level to be used.  Although the specific meaning of the verbosity level is left up  to  individual  SSI
	   modules,  generally	negative  numbers mean no verbose messages, 0 means a minimal set of messages, and positive numbers mean more mes-
	   sages (the greater the positive number, the more output messages will be generated). If left  unspecified  any  any	other  ssi_verbose
	   parameters are specified, the default level of 0 is used.

       If multiple parameters are passed in ssi_verbose, the output will be directed as implied by all the parameters.	If no valid parameters are
       passed (e.g., a single invalid parameter is passed), then output will be directed to stderr by default.

       Also note that as with all SSI parameters, all of these values may be passed by setting the environment variable LAM_SSI_ssi_verbose before
       invoking mpirun.  However, parameters passed through "-ssi ssi_verbose" will take precedence over environment variables.

EXAMPLES

       mpirun -ssi ssi_verbose 1 C foo
	   Since no valid parameters were passed, the verbose output will be sent to stderr.

       mpirun -ssi ssi_verbose file:output.txt,syslogpri:notice C foo
	   Send  the  verbose  output  to  both the file lam-output.txt in the LAM user meta directory as well as to the syslog with a priority of
	   LOG_NOTICE.

SEE ALSO

       lamssi_boot(7), lamssi_coll(7), lamssi_cr(7), lamssi_rpi(7), mpirun(1), lamboot(1), recon(1), lamwipe(1), LAM User's Guide

LAM 7.1.4							    July, 2007								 lamssi(7)