This is a comparison function which is slightly different from the previous cmp functions. This routine is passed the job which the system plans to replace $runningjob and the $host it is running on. The routine is also passed the $candidatejob which is could replace the $runningjob. If developer wants to cancel the preemption, the function must return the value 0, to use the default policy set in the supervisor_preemption_policy setting the function must return a -1. To aggressively preempt the job, the function must return a 2 and for passive preemption the function must return a 1.

    1. 0 = Skip preemption
    2. -1 = Use default preemption setting
    3. 1 = Passively preempt job
    4. 2 = Aggressively preempt job

    The format of the input parameters for jobs and hosts are standard Perl hash structures.

    $job = {
         "id" => 1000,
        "pid" => 1,
        "pgrp" => 1000,
        "priority"=> 2,
        "user" => "username", "status" => "pending", "name" => "my job’s name", "label" => "qube1", "cluster" => "/my/cluster/", "cpus" => 2,
        "prototype" => "cmdline", "requirements" => "", "reservations" => "", "restrictions" => "", "account" => "shotname",
    };
     $host = {
        "name" => "host’s name ",
        "state" => "active",
        "cluster" => "/my/cluster", "resources" => "host.processors=10", "restrictions" => "",
        "address" => "192.168.10.22" 
    }; 

    Important: If you implement this routine in a custom algorithm and mix passive and aggressive preemptions, make sure that the qb_supervisor_preempt_policy is set to "mixed".

    See supervisor_preempt_policy for details.

     


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