[Box-Admins] Runaway ruby process on box3 (was: [squeak-dev]
trunk down again)
David T. Lewis
lewis at mail.msen.com
Sat Nov 9 17:49:11 UTC 2013
On Sat, Nov 09, 2013 at 09:58:33AM +0000, Frank Shearar wrote:
> Any process like that - with /var/lib/jenkins/workspace/ in its path -
> that has been running for more than an hour is a renegade and should
> be shot on sight.
Agreed. I am mainly just reporting these things so that all of us on the
list are aware of issues as they arise. I don't think that any specific
follow-up is required for any of them, aside from keeping them in mind
as we move forward. I have a vague hunch - possibly wrong - that there
is some interaction between the issues we saw on source.squeak.org and
the issues that showed up on build.squeak.org. I have no idea of the
root cause(s) but I expect that if we pay attention to the symptoms
we'll put the pieces of the puzzle together eventually.
Dave
>
> I expect to see two threads in the Ruby process: one for running the
> tests, and a watchdog that is _supposed_ to kill long-running jobs.
>
> As it happens, I realised only yesterday that if you nice something in
> Ruby, through, say, spawn("nice echo 1"), you get the pid of the
> _nice_, not the pid of the _echo_. If you replace "echo" with "invoke
> a squeak", then you can't SIGUSR1 the Squeak because you don't know
> its pid. I removed the nice-ing, in the hope that with the actual pid
> of the squeak process (as opposed to the pid of the nice, its parent),
> I could more reliably kill these jobs.
>
> frank
>
>
> On 9 November 2013 04:44, David T. Lewis <lewis at mail.msen.com> wrote:
> > I killed the runaway ruby process, and confirmed that the InterpreterVM job
> > once again runs successfully.
> >
> > In addition to the ruby process, there are four reparented squeakvm processes
> > that have been running for a couple of days, although not consuming much CPU.
> > I will kill these also. The four processes are:
> >
> > UID PID PPID C STIME TTY TIME CMD
> > jenkins 7983 1 0 Nov07 ? 00:21:01 /var/lib/jenkins/workspace/ReleaseSqueakTrunk/target/Squeak-4.10.2.2614-src-32/bld/squeakvm -vm-sound-null -vm-display-null /var/lib/jenkins/workspac
> > jenkins 8861 1 0 Nov07 ? 00:20:46 /var/lib/jenkins/workspace/ExternalPackages/target/Squeak-4.10.2.2614-src-32/bld/squeakvm -vm-sound-null -vm-display-null /var/lib/jenkins/workspace/
> > jenkins 8972 1 0 Nov07 ? 00:21:06 /var/lib/jenkins/workspace/ExternalPackages/target/Squeak-4.10.2.2614-src-32/bld/squeakvm -vm-sound-null -vm-display-null /var/lib/jenkins/workspace/
> > jenkins 19136 1 0 Nov07 ? 00:15:27 /var/lib/jenkins/workspace/ExternalPackages-Squeak4.3/target/Squeak-4.10.2.2614-src-32/bld/squeakvm -vm-sound-null -vm-display-null /var/lib/jenkins/
> >
> > Dave
> >
> >
> > On Fri, Nov 08, 2013 at 09:16:52PM -0500, David T. Lewis wrote:
> >> Thanks Ken,
> >>
> >> The runaway process is producing no strace output at all, so it is not
> >> making any system calls. According to /proc/28923/status there is a very
> >> large amount of context switching going on:
> >>
> >> nonvoluntary_ctxt_switches: 61281919
> >>
> >> And the process has two active threads.
> >>
> >> I'm going to kill the stuck process and see if that clears up some resource
> >> for the other Jenkins jobs.
> >>
> >> Dave
> >>
> >> On Fri, Nov 08, 2013 at 05:35:47PM -0700, Ken Causey wrote:
> >> > strace and strace64 are now installed on box3. Of course anyone with
> >> > sudo access could have done the same.
> >> >
> >> > Ken
> >> >
> >> > > -------- Original Message --------
> >> > > Subject: Re: [Box-Admins] Runaway ruby process on box3 (was:
> >> > > [squeak-dev] trunk down again)
> >> > > From: "David T. Lewis" <lewis at mail.msen.com>
> >> > > Date: Fri, November 08, 2013 6:23 pm
> >> > > To: Squeak Hosting Support <box-admins at lists.squeakfoundation.org>
> >> > >
> >> > >
> >> > > On Fri, Nov 08, 2013 at 11:16:34PM +0000, Frank Shearar wrote:
> >> > > > On 8 November 2013 23:06, David T. Lewis <lewis at mail.msen.com> wrote:
> >> > > > > On Wed, Nov 06, 2013 at 10:02:38PM -0600, Chris Muller wrote:
> >> > > > >> Trunk stopped responding again. box2 might need to be rebooted again.
> >> > > > >
> >> > > > > We have a ruby process running on box3 that is consuming all available CPU,
> >> > > > > that has been reparented to init, and that has been running for a long time.
> >> > > > >
> >> > > > > jenkins at box3-squeak:~$ ps -aef | grep ruby
> >> > > > > jenkins 19054 18955 0 22:48 pts/1 00:00:00 grep ruby
> >> > > > > jenkins 28923 1 87 Nov06 ? 1-19:18:12 /var/lib/jenkins/.rvm/rubies/ruby-1.9.3-p392/bin/ruby -S rspec test/image_test.rb
> >> > > > > jenkins at box3-squeak:~$ ps -l -p 28923
> >> > > > > F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD
> >> > > > > 0 R 103 28923 1 87 80 0 - 5205 - ? 1-19:18:19 ruby
> >> > > > > jenkins at box3-squeak:~$ top -p 28923 -b -n 1
> >> > > > > top - 22:48:47 up 199 days, 7:38, 2 users, load average: 7.11, 7.11, 7.16
> >> > > > > Tasks: 1 total, 1 running, 0 sleeping, 0 stopped, 0 zombie
> >> > > > > Cpu(s): 2.0%us, 0.2%sy, 2.0%ni, 95.3%id, 0.4%wa, 0.0%hi, 0.0%si, 0.1%st
> >> > > > > Mem: 1032140k total, 1009656k used, 22484k free, 74156k buffers
> >> > > > > Swap: 524280k total, 10732k used, 513548k free, 209540k cached
> >> > > > >
> >> > > > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> >> > > > > 28923 jenkins 20 0 20820 12m 828 R 87.0 1.3 2598:23 ruby
> >> > > > >
> >> > > > > This appears to be a process that got disconnected from one of our Jenkins
> >> > > > > jobs and has been stuck burning cpu for that last couple of days. That also
> >> > > > > happens to be roughly the time frame in which our source.squeak.org service
> >> > > > > got hung up. The Jenkins jobs (e.g. SqueakTrunk) are interacting with
> >> > > > > source.squeak.org, so it is possible that the two problems are related.
> >> > > > >
> >> > > > > I noticed this because the InterpreterVM and CogVM jobs are failing after
> >> > > > > their watchdog timers expire, but the actual jobs succeed if I run them on
> >> > > > > my own local PC. Those jobs run Squeak at low priority (nice) and it is
> >> > > > > possible that their failures are due to the runaway ruby job consuming all
> >> > > > > available resource.
> >> > > > >
> >> > > > > I have not killed the runaway process yet, in case anyone wants to have a
> >> > > > > look at first.
> >> > > >
> >> > > > I would be happy if you attached strace to it, collected some data,
> >> > > > and then killed it. It's a runaway SqueakTrunk job. (Well, it's clear
> >> > > > you know that, but I just had to point it out.) Hopefully the strace
> >> > > > would give enough clues to find what looks like a tight loop...
> >> > > >
> >> > >
> >> > > We don't have strace installed on box3, sorry.
> >> > >
> >> > > Dave
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