clshmctl(1M)

NAME
     clshmctl - Administration tool for CrayLink Shared Memory

SYNOPSIS
     clshmctl startup
     clshmctl shutdown
     clshmctl getcfg
     clshmctl maxjobs <num of jobs>
     clshmctl maxpgs <num of pages>


DESCRIPTION
     clshmctl is a system-administrator's tool for controlling the resources
     associated with CrayLink-shared-memory (clshm) -- a means of cache-
     coherent, shared-memory communication between partitions on an Origin-
     2000.  Each partition of an Origin-2000 has its own hostname, IP address
     and operating-system, and behaves as a stand-alone host.  clshm is meant
     for use by system libraries such as MPI, rather than directly by user-
     applications.

     clshmctl performs various functions needed to administer the software
     devices and daemon associated with clshm and returns operational status
     information.

     clshmctl is invoked with one of the following function names, and the
     associated parameters:


     startup     Configure clshm on the local partition, and start up the
                 clshm devices and clshm daemon (clshmd) with default
                 parameters. The value of the defaults can be examined by
                 using the clshmctl getcfg function, as explained later. The
                 startup step is performed at system boot-up by
                 /etc/init.d/clshm and is required before any inter-partition
                 communication can be effected over CrayLink Shared Memory. It
                 also needs to be done if clshm has been reset by a clshmctl
                 shutdown command.  clshmctl startup also creates and
                 initializes the software devices through which shared-memory
                 communication is performed.



     shutdown    Forces a reset of the clshm software on the local partition.
                 The clshm daemon is made to exit, the resources associated
                 with the clshm software devices are released, and the devices
                 are removed from the hardware-graph filesystem. clshmctl
                 shutdown will fail if any user-program is using any of the
                 clshm devices when this function is called.
     getcfg      Returns the configuration of clshm on the local partition.
                 The parameters configurable through clshmctl are the maximum
                 number of independent channels of shared-memory communication
                 that are simultaneously supported (with a software device
                 corresponding to each channel), and the maximum number of
                 pages of shared-memory that are supported for each channel.


     maxjobs <num of jobs>
                 Sets the maximum number of channels of cross-partition
                 shared-memory on the local partition. The number of jobs
                 specified must be at least 1.  The software devices
                 corresponding to the channels are numbered 0, 1, ... <num of
                 jobs - 1>. maxjobs <num of jobs> will fail if it is called
                 after an open has been called on any of the software devices.


     maxpgs <num of pages>
                 Sets the maximum number of pages of shared memory that can be
                 associated with any of the channels on the local partition.
                 maxpgs <num of pages> will fail if it is called after an open
                 has been called on any of the software devices.



WARNINGS
     Device number 0 is reserved for querying the clshm software, and cannot
     be used for regular inter-partition communication by any library that
     uses clshm. Device number 0 cannot be opened O_EXCL.


SEE ALSO
     clshm_diag(1m), clshmd (1m), mkpart(1m)