Epoll_wait occupying 40% cpu


#1

I used Jupyter and finished some work few days ago. I forgot to shut down the kernel but I notice something strange today. Apparently, the julia process is occupying 40% cpu even though nothing is running.

I diagnosed further with strace and it turns up a bunch of repeated epoll_wait system calls. I don’t mind it goes into a loop but it shouldn’t occupy so much cpu either. Has anyone seen such problem before? This is v0.6.3.

$ strace -p 24868
strace: Process 24868 attached
epoll_wait(5, [], 1024, 52)             = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 52)             = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 52)             = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 60)             = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 61)             = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 62)             = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 62)             = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 0)              = 0
epoll_wait(5, [], 1024, 62)             = 0

top:

   PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
 24868 tkwong    20   0 38.865g 0.028t 0.022t S  46.5  0.9   1730:59 julia
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