# Empty remotechannel and resizing slurm jobs

**URL:** https://discourse.julialang.org/t/empty-remotechannel-and-resizing-slurm-jobs/22816
**Category:** Julia at Scale
**Created:** [April 5, 2019, 8:41pm UTC](https://discourse.julialang.org/t/empty-remotechannel-and-resizing-slurm-jobs/22816 "2019-04-05T20:41:17Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![vancleve](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/vancleve/32/4183_2.png) [@vancleve](https://discourse.julialang.org/u/vancleve)
#### Post date: [April 5, 2019, 8:41pm UTC](https://discourse.julialang.org/t/empty-remotechannel-and-resizing-slurm-jobs/22816/1 "2019-04-05T20:41:17Z")

</div>

I am using RemoteChannels and Distributed for a multicore simulation with the template provided here:  
[https://docs.julialang.org/en/v1/manual/parallel-computing/index.html#Channels-and-RemoteChannels-1](https://docs.julialang.org/en/v1/manual/parallel-computing/index.html#Channels-and-RemoteChannels-1)

Each process can take a few hours so I’d like to resize my Slurm job after the RemoteChannel with the data/parameters to use becomes empty and some of the workers become idle.

Is there any way to do this within julia (i.e., determining when a worker is idle)? I found this:

> [@How to check a RemoteChannel is open?](https://discourse.julialang.org/t/how-to-check-a-remotechannel-is-open/3829/2):
>
> I wasn’t able to find anything about this in the documentation either. However, I ended up with the following pattern. addprocs(3) println(nprocs()) arr = [i for i=1:4] function producer(c::Channel) for item in arr put!(c, item) end end jobs = RemoteChannel(()-\>Channel(producer)); results = RemoteChannel(()-\>Channel(32)); @everywhere function do\_work(jobs, results) while true x = try take!(jobs) end if x == nothing break end …

Is this the best way to get the worker to complete the `do_work` function after the RemoteChannel with the data/parameters becomes empty? I don’t know exactly how RemoteChannels work, so I was wondering if there is some chance that `do_work` here would complete with items still in the RemoteChannel.

If this does work, then I suppose I could have another channel that contains the IDs of the worker and each worker puts its ID there before `do_work` finishes. Then, the main process could use Slurm to resize the job…

Thoughts?