Killed julia process with threads

General Usage
1

I am calculating slices of a multivariate function, with and without threads (here, commented out):

function calculate_slice(f, x, i, xl, xu; n = 50)
    z = range(xl, xu; length = n)
    fz = zeros(n)
    #=Threads.@threads=# for j in 1:n
        y = vcat(x[1:(i-1)], z[j], x[(i+1):end])
        fz[i] = f(y)
    end
    (i = i, xi = x[i], z = z, fz = fz)
end

f here is very CPU- and memory-intensive (about 10K LOC + dependencies, so sorry, no MWE :slight_smile: ).

When I use threads, the julia process ends up killed with no error message. I am using the 1.4-rc branch.

Any hints on debugging this would be appreciated. Would something like this happen if Julia ran out of memory?

2

Is the Out of Memory Killer (OOM) killer being triggered?
On Linux use sudo dmesg to see if this is logged

6 Likes
3

Thanks, that’s what is happening:

$ dmesg | tail -3
[241730.696827] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/user.slice/user-1000.slice/session-c1.scope,task=julia,pid=21662,uid=1000
[241730.696877] Out of memory: Killed process 21662 (julia) total-vm:15685904kB, anon-rss:12200080kB, file-rss:0kB, shmem-rss:0kB
[241731.105188] oom_reaper: reaped process 21662 (julia), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB