[lxc-users] lxd process using lots of CPU

[Stéphane Graber]

On Fri, Mar 10, 2017 at 11:25:40AM +0900, Tomasz Chmielewski wrote:
> On 2017-03-10 03:16, Stéphane Graber wrote:
> 
> > Hmm, then it matches another such report I've seen where some of the
> > threads are reported as using a lot of CPU, yet when trying to trace
> > them you don't actually see anything.
> > 
> > Can you try to run "strace -p" on the various threads that are reported
> > as eating all your CPU?
> > 
> > The similar report I got of this would just show them stuck on a futex,
> > which wouldn't explain the CPU use. And unfortunately it looked like
> > tracing the threads actually somehow fixed the CPU problem for that
> > user...
> > 
> > 
> > If you just want the problem gone, "systemctl restart lxd" should fix
> > things without interrupting your containers, but we'd definitely like to
> > figure this one out if we can.
> 
> Yes, restarting lxd fixed it.
> 
> stracing different threads was showing a similar output to what I've pasted
> before. Stuck in some kind of loop?

That'd be some kind of loop which doesn't involve any syscall, so
certainly possible but we don't exactly have many of those in the LXD
code base and none seem like good candidates.


We'd definitely love to fix this but short of having a reliable
reproducer or at least debug logs of the time at which the daemon
started misbehaving, it's going to be near impossible to track down...

-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 801 bytes
Desc: not available
URL: <http://lists.linuxcontainers.org/pipermail/lxc-users/attachments/20170309/08d9f39e/attachment.sig>