Problems interrupting pmap with Ctrl-C #6752
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amitmurthy opened this Issue on May 5, 2014 · 7 comments
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0.4.x
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@amitmurthy
@vtjnash
@StefanKarpinski
@simonster
@ihnorton
@tkelman
@bjarthur
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@amitmurthy
The Julia Language member
amitmurthy commented on May 5, 2014 • edited

Unable to interrupt a pmap call with 2 or more workers

julia> addprocs(2)
julia> pmap(x-> while true; sleep(2000); end, 1:4)
^C^C^C^C^C^C^C^C^C^C^C^C

I added a debug statement to the sigint handler as well as the try-catch block in pmap. Looks like while the sigint handler is called everytime, only one the async tasks in pmap (for the first Ctrl-C) is being interrupted.

julia> addprocs(2)
julia> pmap(x-> while true; sleep(2000); end, 1:4)
^Cjl_defer_signal 0, jl_signal_pending 0, sig 2
InterruptException()
^Cjl_defer_signal 0, jl_signal_pending 0, sig 2
^Cjl_defer_signal 0, jl_signal_pending 0, sig 2
^Cjl_defer_signal 0, jl_signal_pending 0, sig 2
....

Are all the tasks interrupted upon a Ctrl-C? If so, then it could be a REPL bug too.

If not, the "main" task, which in the case of pmap is the REPL waiting on a @sync block should be interrupted, instead of a @async task chosen at random.
@vtjnash
The Julia Language member
vtjnash commented on May 5, 2014

^C interrupts the currently executing task, which may be the last worker to block

@JeffBezanson maybe InterruptException should be propagated to the root task, if the current task is in the uv_run scheduler?
@StefanKarpinski
The Julia Language member
StefanKarpinski commented on Jun 12, 2014

Bump. Would be nice to have a fix for this. Interrupting a long-running distributed task is pretty common.
@JeffBezanson JeffBezanson referenced this issue on Jun 16, 2014
Closed
Parallel and time macro segfault #7261
@simonster simonster added this to the 0.4 milestone on Aug 1, 2014
@simonster simonster added the parallel label on Aug 1, 2014
@simonster
The Julia Language member
simonster commented on Sep 26, 2014

Bump. This is really annoying.
@ihnorton ihnorton added the bug label on Dec 30, 2014
@ihnorton
The Julia Language member
ihnorton commented on Dec 30, 2014

Related (dupe?) #6283
@tkelman
The Julia Language member
tkelman commented on May 12

@amitmurthy have recent refactorings improved the situation here at all?
@vtjnash vtjnash added a commit that referenced this issue on Jun 13
	@vtjnash 	reconnect REPL backend consumer reference to client.jl
			8df4c40
@bjarthur
bjarthur commented on Jun 15

possibly fixed. i get the following error on OS X for the latest master, and sth similar on linux:

julia> addprocs(2)
2-element Array{Int64,1}:
 2
 3

julia> pmap(x-> while true; sleep(2000); end, 1:4)
^C^C^C^Cfatal: error thrown and no exception handler available.
InterruptException()
jl_run_once at /Users/arthurb/src/julia/src/jl_uv.c:141
process_events at ./libuv.jl:82
wait at ./event.jl:100
task_done_hook at ./task.jl:161
unknown function (ip: 0x31ee9ecd9)
jl_call_method_internal at /Users/arthurb/src/julia/src/./julia_internal.h:93
jl_apply at /Users/arthurb/src/julia/src/./julia.h:1384
^C^C
atexit hook threw an error: InterruptException()^Cjl_uv_writecb() ERROR: bad file descriptor EBADF
jl_uv_writecb() ERROR: bad file descriptor EBADF
jl_uv_writecb() ERROR: bad file descriptor EBADF
jl_uv_writecb() ERROR: bad file descriptor EBADF
jl_uv_writecb() ERROR: bad file descriptor EBADF
^Cjl_uv_writecb() ERROR: bad file descriptor EBADF
jl_uv_writecb() ERROR: bad file descriptor EBADF
jl_uv_writecb() ERROR: bad file descriptor EBADF
jl_uv_writecb() ERROR: bad file descriptor EBADF
jl_uv_writecb() ERROR: bad file descriptor EBADF

@bjarthur
bjarthur commented on Jun 15

hold on. while on OS X it does return me to the command line, on linux it does not. rather, it keeps repeating the error message over and over.
@vtjnash vtjnash added a commit that closed this issue on Jun 15
	@vtjnash 	reconnect REPL backend consumer reference to client.jl
	
		0d519e1
@vtjnash vtjnash closed this in 0d519e1 on Jun 15
@tkelman tkelman added the needs-tests label on Jun 15