> Idle limits are mostly good. This mostly limits the number of each > > users jobs that maui will consider in any scheduling cycle so it make > > the scheduling cycle shorter/faster. It also limits the priority > > accumulated by queued jobs and alleviates 'queue stuffing'. I'd > > recommend idle limits given that maui does not contain a better > > facility to handle such issues. > > Yep, a short queue reduces maui stress. I completely agree that. > Seting a limit of 100 jobs per user leaves a 1k idle queue in normal > behaviour, when many user are running jobs. That's the limit I'd use. > > > But, as I've never tried this before, let me ask how maui will behave > in this situation: > > > if the farm is 70%, and I have only two users who have submited jobs > (user A and B). User A has much more priority than user B, so let's say > that the 30% must be filled with 25% of jobs from user A and 5% jobs > from user B, if I have 1000 jobs in queue (500 from A and 500 from B) > IDLE queue will contain 100 jobs of each user, so each scheduling > cycle is going to schedule 200 jobs, is maui going to fill up the farm > respecting our policies (25/5)? or is it going to start 100 jobs from > each user on each scheduling cycle filling up the farm 15% and 15%? >
I've worked in an example: QoS Target: QOS ------------- lhcatlas* -- 47.42 (user atprd) magic* -- 3.80 (user maprd) I set a limit of 5 jobs per user. I use only one node with 10/20/40 "cpus". 80 jobs each user. np=10) # qstat |grep R|grep -c map 5 # qstat |grep R|grep -c at 5 QOS ------------- lhcatlas 50.00 47.42 50.00 magic* 50.00 3.80 50.00 np=20) # qmgr -c "s n pbs01-test.pic.es np=20" # qstat |grep R|grep -c map 10 # qstat |grep R|grep -c at 10 QOS ------------- lhcatlas 50.00 47.42 50.00 magic* 50.00 3.80 50.00 np=40) # qmgr -c "s n pbs01-test.pic.es np=40" # qstat |grep R|grep -c ma 20 # qstat |grep R|grep -c at 20 QOS ------------- lhcatlas 50.00 47.42 50.00 50.00 50.00 magic* 50.00 3.80 50.00 50.00 50.00 Without the limit FS is respected. Maybe my conf is wrong, but this behaviour is why I'm afraid of limitng idle queue. Cheers, Arnau
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