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Re: [Condor-users] Is it possible to ignore any priority setting?

On Tue, Sep 7, 2010 at 10:36 AM, Genie Jhang <geniejhang@xxxxxxxxxxx> wrote:

I'd like to set our machines to execute jobs which are added earlier regardless of any priority.

Is it possible?

Yes and no.

You can put all your jobs in to the same group and set auto-regroup to be off. This essentially gives every job from every user the same priority -- the group's priority. But it doesn't guarantee FIFO execution, just FIFO consideration of your jobs. Condor will try to find a place for job N, but if it can't it'll move on and look for a place for job N+1 (assuming it's got a different requirement profile from job N). So N+1 could still end up running before N just because N was blocked on some rare slot type.

And even then all of this is only really controllable within one condor_schedd instance. If you have multiple condor_schedd instances all bets are off because Condor negotiations with one schedd, then the next one, then the next one and so on so the oldest jobs in your system might be on the Nth schedd that gets serviced last by the negotiator.

You can use preemption to set things right, so that older jobs can always preempt newer jobs. But then you've got wasted cycles if your jobs aren't checkpoint-able in some fashion (either by running in the standard universe, java universe or VM universe).

- Ian

Cycle Computing, LLC
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