[GE users] "h_rt" or "s_rt" for predicting job end times

brs brs at usf.edu
Thu Feb 12 14:44:16 GMT 2009


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Neil,

IIRC, They should both override default_duration (in the sched_conf) in 
order to tell the scheduler "how long" a job should run. The difference 
is that s_rt will send a SIGUSR1 to your process some time before it 
sends a SIGTERM. This allows you to implement a signal handler in your 
job to properly handle job termination. This value is set in the queue 
configuration in the 'notify' field. h_rt does not provide a SIGUSR1 
and, I believe, sends a SIGKILL to the processes, terminating them 
ungracefully. This can be bad if any of your jobs catch SIGTERM in order 
to facilitate a clean-up process before exiting, BUT I have not seen 
very many codes that catch SIGTERM or SIGUSR1 (on our system at least) 
and so most of our users use h_rt.

Best Regards,
Brian Smith

futurity wrote:
>
> Hi,
>
> We?re using Grid Engine 6.1 and need some help deciding which out of 
> "h_rt" and "s_rt" our jobs should be using in order to help the 
> scheduler predict when jobs will finish.
>
> When I posted recently about our reservation problems, Reuti suggested 
> I look into using ?h_rt?. Unfortunately the Admin and User PDF guides 
> don?t contain any information on either "h_rt" or "s_rt", so I had to 
> experiment to find out what it does.
>
> From my experiments, it appears that ?h_rt? sets a run time per job, 
> which is used by the scheduler to predict when jobs finish. 
> Unfortunately, it causes jobs to be terminated if they run for longer 
> than this specified time. I?m guessing that ?h_? stands for a hard 
> limit and this is why jobs are terminated when then exceed this?
>
> I?m guessing that ?s_rt? is a soft limit? I?m hoping that this means 
> that once the time specified by the job is reached, that it does ?NOT? 
> terminate the job? i.e. if the user specified the wrong time limit by 
> accident, or the job ran slower for some reason, that the job would be 
> allowed to continue running?
>
> Does anyone know if ?s_rt? is also used by the scheduler in the same 
> way that ?h_rt? is used and if the only difference would be that one 
> terminates and the other doesn?t?
>
> Sorry for all these questions but I can?t seem to find any 
> documentation on these two settings. If anyone can point me at some 
> documentation it would be really appreciated.
>
> Many thanks,
>
> Neil
>


-- 
Brian Smith
Sr. HPC Systems Administrator
Research Computing, University of South Florida
4202 E. Fowler Ave. ENB308 
Office Phone: +1 813 974-1467
Organization URL: http://rc.usf.edu

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