Difference between poll_s and ep_poll WCHAN in ps output
8,859
To display a bit more of the WCHAN
function name, you can use e.g.:
ps -e -o pid,wchan=WIDE-WCHAN-COLUMN -o comm
This will show you the two functions are ep_poll
and poll_schedule_timeout
.
The first is in fs/eventpoll.c
in the kernel, and is related to epoll
facility, specifically to the epoll_wait
system call.
The other is in fs/select.c
and will be used both for the "plain" poll
system call, and for select
.
So they are both "waiting for something I/O-related to happen" wait states, but for different system facilities.
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Author by
User007
Updated on September 18, 2022Comments
-
User007 over 1 year
When I issue
ps -elf|grep python
for example on my system, I see these:1 S 1000 6020 6008 0 80 0 - 9914 poll_s Jul12 ? 00:00:01 python manage.py run_gunicorn -t 3600 -w 8 -b 127.0.0.1:8000 0 S 1000 22496 22491 0 80 0 - 10477 ep_pol 12:32 ? 00:00:10 /var/lib/mywebapp/env/bin/python /var/lib/mywebapp/env/bin/pserve development.ini
What is the difference between
poll_s
andep_pol
? -
Mat almost 12 yearsThis answer assumes the question was about Linux...
-
Gilles 'SO- stop being evil' almost 12 yearsI think the output format given for
ps -elf
guarantees Linux.