NAME

xxqs_name_sxx_sched_conf - xxQS_NAMExx default scheduler configuration file

DESCRIPTION

sched_conf defines the configuration file format for xxQS_NAMExx's scheduler. In order to modify the configuration use qconf(1) -msconf command. A default configuration is provided together with the xxQS_NAMExx distribution package.

Note, xxQS_NAMExx allows backslashes (\) be used to escape newline (\newline) characters. The backslash and the newline are replaced with a space (" ") character before any interpretation.

FORMAT

The following parameters are recognized by the xxQS_NAMExx scheduler if present in sched_conf:

algorithm

Note: Deprecated, may be removed in future release. Allows for the selection of alternative scheduling algorithms.

Currently default is the only allowed setting.

load_formula

A simple algebraic expression used to derive a single weighted load value from all or part of the load parameters reported by xxqs_name_sxx_execd(8) for each host and from all or part of the consumable resources (see xxqs_name_sxx_complex(5)) being maintained for each host. The load formula expression syntax is that of a summation weighted load values, that is:

{w1|load_val1[*w1]}[{+|-}{w2|load_val2[*w2]}[{+|-}...]]

Note, no blanks are allowed in the load formula. The load values and consumable resources (load_val1, ...) are specified by the name defined in the complex (see xxqs_name_sxx_complex(5)).
Note: Administrator defined load values (see the load_sensor parameter in xxqs_name_sxx_conf(5) for details) and consumable resources available for all hosts (see xxqs_name_sxx_complex(5)) may be used as well as xxQS_NAMExx default load parameters.
The weighting factors (w1, ...) are positive integers. After the expression is evaluated for each host the results are assigned to the hosts and are used to sort the hosts corresponding to the weighted load. The sorted host list is used to sort queues subsequently. The default load formula is "np_load_avg".

job_load_adjustments

The load, which is imposed by the xxQS_NAMExx jobs running on a system varies in time, and often, e.g. for the CPU load, requires some amount of time to be reported in the appropriate quantity by the operating system. Consequently, if a job was started very recently, the reported load may not provide a sufficient representation of the load which is already imposed on that host by the job. The reported load will adapt to the real load over time, but the period of time, in which the reported load is too low, may already lead to an oversubscription of that host. xxQS_NAMExx allows the administrator to specify job_load_adjustments which are used in the xxQS_NAMExx scheduler to compensate for this problem.
The job_load_adjustments are specified as a comma separated list of arbitrary load parameters or consumable resources and (separated by an equal sign) an associated load correction value. Whenever a job is dispatched to a host by the scheduler, the load parameter and consumable value set of that host is increased by the values provided in the job_load_adjustments list. These correction values are decayed linearly over time until after load_adjustment_decay_time from the start the corrections reach the value 0. If the job_load_adjustments list is assigned the special denominator NONE, no load corrections are performed.
The adjusted load and consumable values are used to compute the combined and weighted load of the hosts with the load_formula (see above) and to compare the load and consumable values against the load threshold lists defined in the queue configurations (see xxqs_name_sxx_queue_conf(5)). If the load_formula consists simply of the default CPU load average parameter np_load_avg, and if the jobs are very compute intensive, one might want to set the job_load_adjustments list to np_load_avg=1.00, which means that every new job dispatched to a host will require 100 % CPU time, and thus the machine's load is instantly increased by 1.00.

load_adjustment_decay_time

The load corrections in the job_load_adjustments list above are decayed linearly over time from the point of the job start, where the corresponding load or consumable parameter is raised by the full correction value, until after a time period of load_adjustment_decay_time, where the correction becomes 0. Proper values for load_adjustment_decay_time greatly depend upon the load or consumable parameters used and the specific operating system(s). Therefore, they can only be determined on-site and experimentally. For the default np_load_avg load parameter a load_adjustment_decay_time of 7 minutes has proven to yield reasonable results.

maxujobs

The maximum number of jobs any user may have running in a xxQS_NAMExx cluster at the same time. If set to 0 (default) the users may run an arbitrary number of jobs.

schedule_interval

At the time the scheduler thread initially registers at the event master thread in xxqs_name_sxx_qmaster(8) process schedule_interval is used to set the time interval in which the event master thread sends scheduling event updates to the scheduler thread. A scheduling event is a status change that has occurred within xxqs_name_sxx_qmaster(8) which may trigger or affect scheduler decisions (e.g. a job has finished and thus the allocated resources are available again). In the xxQS_NAMExx default scheduler the arrival of a scheduling event report triggers a scheduler run. The scheduler waits for event reports otherwise.
schedule_interval is a time value (see xxqs_name_sxx_queue_conf(5) for a definition of the syntax of time values).

queue_sort_method

This parameter determines in which order several criteria are taken into account to product a sorted queue list. Currently, two settings are valid: seqno and load. However in both cases, xxQS_NAMExx attempts to maximize the number of soft requests (see qsub(1) -s option) being fulfilled by the queues for a particular as the primary criterion.
Then, if the queue_sort_method parameter is set to seqno, xxQS_NAMExx will use the seq_no parameter as configured in the current queue configurations (see xxqs_name_sxx_queue_conf(5)) as the next criterion to sort the queue list. The load_formula (see above) has only a meaning if two queues have equal sequence numbers. If queue_sort_method is set to load the load according theload_formula is the criterion after maximizing a job's soft requests and the sequence number is only used if two hosts have the same load. The sequence number sorting is most useful if you want to define a fixed order in which queues are to be filled (e.g. the cheapest resource first).

The default for this parameter is load.

halftime

When executing under a share based policy, the scheduler "ages" (i.e. decreases) usage to implement a sliding window for achieving the share entitlements as defined by the share tree. The halftime defines the time interval in which accumulated usage will have been decayed to half its original value. Valid values are specified in hours or according to the time format as specified in xxqs_name_sxx_queue_conf(5). If the value is set to 0, the usage is not decayed.

usage_weight_list

xxQS_NAMExx accounts for the consumption of the resources CPU-time, memory and IO to determine the usage which is imposed on a system by a job. A single usage value is computed from these three input parameters by multiplying the individual values by weights and adding them up. The weights are defined in the usage_weight_list. The format of the list is

cpu=wcpu,mem=wmem,io=wio

where wcpu, wmem and wio are the configurable weights. The weights are real number. The sum of all tree weights should be 1.

compensation_factor

Determines how fast xxQS_NAMExx should compensate for past usage below of above the share entitlement defined in the share tree. Recommended values are between 2 and 10, where 10 means faster compensation.

weight_user

The relative importance of the user shares in the functional policy. Values are of type real.

weight_project

The relative importance of the project shares in the functional policy. Values are of type real.

weight_department

The relative importance of the department shares in the functional policy. Values are of type real.

weight_job

The relative importance of the job shares in the functional policy. Values are of type real.

weight_tickets_functional

The maximum number of functional tickets available for distribution by xxQS_NAMExx. Determines the relative importance of the functional policy. See under xxqs_name_sxx_priority(5) for an overview on job priorities.

The maximum number of share based tickets available for distribution by xxQS_NAMExx. Determines the relative importance of the share tree policy. See under xxqs_name_sxx_priority(5) for an overview on job priorities.

weight_deadline

The weight applied on the remaining time until a jobs latest start time. Determines the relative importance of the deadline. See under xxqs_name_sxx_priority(5) for an overview on job priorities.

weight_waiting_time

The weight applied on the jobs waiting time since submission. Determines the relative importance of the waiting time. See under xxqs_name_sxx_priority(5) for an overview on job priorities.

weight_urgency

The weight applied on jobs normalized urgency when determining priority finally used. Determines the relative importance of urgency. See under xxqs_name_sxx_priority(5) for an overview on job priorities.

weight_priority

The weight applied on jobs normalized POSIX priority when determining priority finally used. Determines the relative importance of POSIX priority. See under xxqs_name_sxx_priority(5) for an overview on job priorities.

weight_ticket

The weight applied on normalized ticket amount when determining priority finally used. Determines the relative importance of the ticket policies. See under xxqs_name_sxx_priority(5) for an overview on job priorities.

flush_finish_sec

The parameters are provided for tuning the system's scheduling behavior. By default, a scheduler run is triggered in the scheduler interval. When this parameter is set to 1 or larger, the scheduler will be triggered x seconds after a job has finished. Setting this parameter to 0 disables the flush after a job has finished.

flush_submit_sec

The parameters are provided for tuning the system's scheduling behavior. By default, a scheduler run is triggered in the scheduler interval. When this parameter is set to 1 or larger, the scheduler will be triggered x seconds after a job was submitted to the system. Setting this parameter to 0 disables the flush after a job was submitted.

schedd_job_info

The default scheduler can keep track why jobs could not be scheduled during the last scheduler run. This parameter enables or disables the observation. The value true enables the monitoring false turns it off.

It is also possible to activate the observation only for certain jobs. This will be done if the parameter is set to job_list followed by a comma separated list of job ids.

The user can obtain the collected information with the command qstat -j.

params

This is foreseen for passing additional parameters to the xxQS_NAMExx scheduler.

Changing params will take immediate effect. The default for params is none.

The following values are recognized:

DURATION_OFFSET

If set, overrides the default of value 60 seconds. This parameter is used by the xxQS_NAMExx scheduler when planning resource utilization as the delta between net job runtimes and total time until resources become available again. Net job runtime as specified with -l h_rt=... or -l s_rt=... or default_duration always differs from total job runtime due to delays before and after actual job start and finish. Among the delays before job start is the time until the end of a schedule_interval, the time it takes to deliver a job to sge_execd(8) and the delays caused by prolog in xxqs_name_sxx_queue_conf(5), start_proc_args in xxqs_name_sxx_pe(5) and starter_method in xxqs_name_sxx_queue_conf(5)

(notify, terminate_method or checkpointing), procedures run after actual job finish, such as stop_proc_args in xxqs_name_sxx_pe(5) or epilog in xxqs_name_sxx_queue_conf(5) , and the delay until a new schedule_interval.
If the offset is too low, resource reservations (see max_reservation) can be delayed repeatedly due to an overly optimistic job circulation time.

PROFILE

If set equal to 1, the scheduler logs profiling information summarizing each scheduling run.

MONITOR

If set equal to 1, the scheduler records information for each scheduling run allowing to reproduce job resources utilization in the file <xxqs_name_sxx_root>/<cell>/common/schedule.

PE_RANGE_ALG

This parameter sets the algorithm for the pe range computation. The default is automatic, which means that the scheduler will select the best one, and it should not be necessary to change it to a different setting in normal operation. If a custom setting is needed, the following values are available:

auto : the scheduler selects the best algorithm
least : starts the resource matching with the lowest slot amount first
bin : starts the resource matching in the middle of the pe slot range
highest : starts the resource matching with the highest slot amount first

reprioritize_interval

Interval (HH:MM:SS) to reprioritize jobs on the execution hosts based on the current ticket amount for the running jobs. If the interval is set to 00:00:00 the reprioritization is turned off (default). If dynamic priority adjustments are disabled then newly started jobs will get the queues priority applied. For already running jobs the last dynamic priority adjustment remains valid until the job finishes.

The reprioritization tickets are calculated by the scheduler and update events for running jobs are only sent after the scheduler calculated new values. How often the schedule should calculate the tickets is defined by the reprioritize_interval. Because the scheduler is only triggered in a specific interval (scheduler_interval) this means the reprioritize_interval has only a meaning if set greater than the scheduler_interval. For example, if the scheduler_interval is 2 minutes and reprioritize_interval is set to 10 seconds, this means the jobs get re-prioritized every 2 minutes.

report_pjob_tickets

This parameter allows to tune the system's scheduling run time. It is used to enable / disable the reporting of pending job tickets to the qmaster. It does not influence the tickets calculation. The sort order of jobs in qstat is only based on the submit time, when the reporting is turned off. The reporting should be turned off in a system with a very large amount of jobs by setting this parameter to "false".

halflife_decay_list

The halflife_decay_list allows to configure different decay rates for the "finished_jobs usage types, which is used in the pending job ticket calculation to account for jobs which have just ended. This allows the user the pending jobs algorithm to count finished jobs against a user or project for a configurable decayed time period. This feature is turned off by default, and the halftime is used instead. The halflife_decay_list also allows one to configure different decay rates for each usage type being tracked (cpu, io, and mem). The list is specified in the following format:

<USAGE_TYPE>=<TIME>[:<USAGE_TYPE>=<TIME>[:<USAGE_TYPE>=<TIME>]]

<USAGE_TYPE> can be one of the following: cpu, io, or mem. <TIME> can be -1, 0 or a timespan specified in minutes. If <TIME> is -1, only the usage of currently running jobs is used. 0 means that the usage is not decayed.

policy_hierarchy

This parameter sets up a dependency chain of ticket based policies. Each ticket based policy in the dependency chain is influenced by the previous policies and influences the following policies. A typical scenario is to assign precedence for the override policy over the share-based policy. The override policy determines in such a case how share-based tickets are assigned among jobs of the same user or project. Note that all policies contribute to the ticket amount assigned to a particular job regardless of the policy hierarchy definition. Yet the tickets calculated in each of the policies can be different depending on "POLICY_HIERARCHY".

The "POLICY_HIERARCHY" parameter can be a up to 3 letter combination of the first letters of the 3 ticket based policies S(hare-based), F(unctional) and O(verride). So a value "OFS" means that the override policy takes precedence over the functional policy, which finally influences the share-based policy. Less than 3 letters mean that some of the policies do not influence other policies and also are not influenced by other policies. So a value of "FS" means that the functional policy influences the share-based policy and that there is no interference with the other policies.

The special value "NONE" switches off policy hierarchies.

If set to "true" or "1", override tickets of any override object instance are shared equally among all running jobs associated with the object. The pending jobs will get as many override tickets, as they would have, when they were running. If set to "false" or "0", each job gets the full value of the override tickets associated with the object. The default value is "true".

If set to "true" or "1", functional shares of any functional object instance are shared among all the jobs associated with the object. If set to "false" or "0", each job associated with a functional object, gets the full functional shares of that object. The default value is "true".

max_functional_jobs_to_schedule

The maximum number of pending jobs to schedule in the functional policy. The default value is 200.

max_pending_tasks_per_job

The maximum number of subtasks per pending array job to schedule. This parameter exists in order to reduce scheduling overhead. The default value is 50.

max_reservation

The maximum number of reservations scheduled within a schedule interval. When a runnable job can not be started due to a shortage of resources a reservation can be scheduled instead. A reservation can cover consumable resources with the global host, any execution host and any queue. For parallel jobs reservations are done also for slots resource as specified in xxqs_name_sxx_pe(5). As job runtime the maximum of the time specified with -l h_rt=... or -l s_rt=... is assumed. For jobs that have neither of them the default_duration is assumed. Reservations prevent jobs of lower priority as specified in xxqs_name_sxx_priority(5) from utilizing the reserved resource quota during the time of reservation. Jobs of lower priority are allowed to utilize those reserved resources only if their prospective job end is before the start of the reservation (backfilling). Reservation is done only for non-immediate jobs (-now no) that request reservation (-R y). If max_reservation is set to "0" no job reservation is done.

Note, that reservation scheduling can be performance consuming and hence reservation scheduling is switched off by default. Since reservation scheduling performance consumption is known to grow with the number of pending jobs, the use of -R y option is recommended only for those jobs actually queuing for bottleneck resources. Together with the max_reservation parameter this technique can be used to narrow down performance impacts.

default_duration

When job reservation is enabled through max_reservation xxqs_name_sxx_sched_conf(5) parameter the default duration is assumed as runtime for jobs that have neither -l h_rt=... nor -l s_rt=... specified. In contrast to a h_rt/s_rt time limit the default_duration is not enforced.

FILES

For a complete list of files used by all xxQS_NAMExx commands, see xxqs_name_sxx_intro(1).

<xxQS_NAME_Sxx_ROOT>/<xxQS_NAME_Sxx_CELL>/common/sched_configuration

scheduler thread configuration

COPYRIGHT

See xxqs_name_sxx_intro(1) for a full statement of rights and permissions.