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  messages  (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