Hello,
we have a very peculiar array job scheduling problem.
Cluster: Very heterogeneous SGE cluster with different types of workstations.
Problem: One array job can use more job slots than two array jobs together.
Example: User A submitted an array job, 64 array tasks were running at
the same time. Then user B submitted a similar array job and after a
while each of the jobs was running with approx 28 array tasks. According
to the users the problem gets worse with each array job. Terminating one
of the jobs immediately leads to the normal usage again.
Question: Does anybody know if the "job_load_adjustment" of array jobs
depends only on number of tasks or if the number of jobs is taken into
account as well?
From my point of view limits, quotas, etc. cannot be the cause of the
problem because then the total of job slots being used by two jobs could
not be less then the job slots being used by one single job. The
scheduler configuration though was not made for short array jobs but for
longer running parallel jobs on interactively used workstations.
Next I will try to observe the "artifitial" load dependend on the number
of array jobs and tasks - but maybe someone has a good explanation.
Many thanks!
Erik Soyez.
Some details:
[Queue]
load_thresholds np_load_avg=0.75
suspend_thresholds NONE
priority 10
[Scheduler]
algorithm default
schedule_interval 0:0:15
maxujobs 0
queue_sort_method seqno
job_load_adjustments np_load_avg=0.90
load_adjustment_decay_time 0:2:30
load_formula np_load_avg
schedd_job_info true
flush_submit_sec 2
flush_finish_sec 2
params none
reprioritize_interval 0:0:0
halftime 168
usage_weight_list cpu=1.000000,mem=0.000000,io=0.000000
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