Am 24.04.2007 um 14:30 schrieb Toon Knapen:
Tim Cutts wrote:
but what if you have a bi-cpu bi-core machine to which you assign
4 slots. Now one slot is being used by a process which performs
heavy IO. Suppose another process is launched that performs heavy
IO. In that case the latter process should wait until the first
one is done to avoid slowing down the efficiency of the system.
Generally however, clusters take only time and memory
requirements into account.
I think that varies. LSF records the current I/O of a node as one
of its load indices, so you can request a node which is doing less
than a certain amount of I/O. I imagine the same is true of SGE,
but I wouldn't know.
Indeed, using SGE you could also take this into account. However if
someone submits 4 jobs, the jobs do not directly start to generate
heavy I/O. So the scheduler might think that the 4 jobs can easily
coexist on this same node. However, after a few minutes all 4 jobs
start eating disk BW and slow the node down horribly. What would
your suggestion be to solve this ?
In SGE it's possible to put some "job_load_adjustments" with
"load_adjustment_decay_time" to take this into account. This will
show some virtual load (not necessarily the CPU load) during the
first minutes of the job. Only odd thing would be, if they were
scheduled in the same cycle to the same node.
-- Reuti
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