NAME

migcmd − Print or update information relating to process migration

SYNOPSIS

migcmd [−sSZptT] [−[IE] (none|all|root)] [−[il] (0|1)] [−l (0|1)] [−P numRecs] [−d debugLevel] [−V migrationVersion]

OPTIONS

−sA message is printed to indicate the status of process migration on the current host, including the migration level and the conditions under which migration is permitted. 

−SMigration statistics are printed.  These include such values as the average time to migrate an active process, the average time to perform a remote exec, and the total number of migrations, evictions, and remote execs performed. 

−ZThe kernel migrations statistics are reset to 0. 

−IChange the import restrictions for process migration.  (The caller must be root.) 

−EChange the export restrictions for process migration.  (The caller must be root.) 

−iChange whether idle time is considered when determining the availability of this host.  (The caller must be root.) 

−lChange whether load average is considered when determining the availability of this host.  (The caller must be root.) 

−pProcess migration trace records are printed.  The number of records may be altered by the −P option. 

−P numRecsThe number of trace records to print is modified to be numRecs.  This option must be used with the −p option. 

−tProcess migration tracing is enabled for the current host. 

−TProcess migration tracing is disabled for the current host. 

−d debugLevelThe kernel process migration debug level is set to debugLevel. 

−V migrationVersionThe kernel process migration version is set to migrationVersion.  The caller must be root. 

INTRODUCTION

This command is used to perform functions related to process migration.  Migcmd  is normally used to print the status of process migration availability or migration statistics.  Migcmd may also be used to restrict which users may export or import processes from or to the local host (the caller must be root to do so); change whether load average and/or idle time are considered when deciding whether the current host is available for imports; print process migration trace  records; enable or disable tracing of process migration activity; or set the kernel’s migration “debugging level” or “migration version”. 

MIGRATION STATE

Migcmd prints the status of process migration availability if the −s flag is specified.  As root, one may modify the restrictions on process migration.  For both exporting and importing processes, root may choose to restrict migration to processes owned by root, or not allow migration at all, or allow all users to migrate.  These options are specified to the −E and −I flags as root, none, and all respectively.  In addition, root is permitted to instruct the loadavg daemon whether to consider idle time and/or load average when announcing the availability of the host for importation.  These options are −i and −l, respectively, and take an integer argument: 1 specifies that the criterion should be ignored, and 0 specifies that it should be considered. 

STATISTICS

The -S flag causes Migcmd  to print statistics on its standard output.  These statistics change too rapidly to list the format here.  The format is (hopefully) self-explanatory. 

TRACING

The −p flag may be used to dump process migration trace records.  The maximum number of records defaults to 200 but may be modified with the −P option.  By default, tracing is disabled and no trace records will be printed.  To enable tracing, one may specify the −t flag, and to disable it, one may specify the −T flag. 

MIGRATION DEBUG LEVEL

The kernel’s debug level may be modified using the −d  option.  Subsequently higher values for the debug level will cause more debugging statements to be executed. For example, to have no migration debugging enabled whatsoever, the level may be set to 0.  To enable error messages that indicate unusual but non-fatal events, the level may be 2 (this is the current default).  To enable more messages about the internal operation of migration within the kernel, such as forwarded system calls, the level may be set to values from 3-10.  “Less interesting” events are conditioned on higher values of the debug level. 

MIGRATION VERSION

The kernel’s migration version may be modified by root using the −V  option.  This should be done only when the kernel is compiled with an incorrect version for some reason, in order to cause the kernel to be compatible vis-a-vis migration with a different class of kernels. 

SEE ALSO

mig

KEYWORDS

debug level, eviction, process migration, remote execution

Sprite version 1.0  —  February 16, 1990