Thanks for your patience, David, and for the very useful training.

OK. I like a challenge!
I found that the debugfs was already mounted and that I had missed copying the diagnose.shutdown script into /usr/lib/systemd/system-shutdown/

Now I have a log file which shows the sequence of the shutdown process and a "Schrodinger's cat" conundrum (I prefer the term Schrondinbug, because I like cats).
The tuned process is halted about 1.1 seconds into the shutdown (see attached). So now I know how it should work.
I suppose it's now a matter of throwing in some other random processes to make it not work again????
Any suggestions?

Cheers
Bill

-----Original message-----
> From:David Sommerseth <[log in to unmask]>
> Sent: Sunday 22nd January 2017 7:38
> To: Bill Maidment <[log in to unmask]>; [log in to unmask]
> Subject: Re: SL7.3RC2 shutdown slow
> 
> On 21/01/17 05:16, Bill Maidment wrote:
> > He! He! He!
> > I've installed the shutdown diagnostic and on reboot there is no delay on shutdown!
> > Unfortunately, ftrace was not installed, so I couldn't analyse what was not happening.
> 
> Ftrace is a kernel component which is enabled by default.  But you need
> to have the debugfs mounted at the appropriate place.  For more info:
> <https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Developer_Guide/ftrace.html>
> 
> > I removed the diagnostic and the shutdown delay returned.
> > So it seems that the more you search for something, the more it goes away.
> > I am out of my depth now, so I'll leave this issue as an exercise for the brave.
> 
> Oh, those are "funny" ... and they are usually called Heisenbugs ...
> <https://en.wikipedia.org/wiki/Heisenbug>
> 
> I would then look more carefully at what this shutdown diagnostics
> enables under the hood ... and see if you can figure out what triggers
> the delay to disappear.  Or if it is just as simple as something being
> shutdown in the wrong order and a delay somewhere avoids a little
> timeout causing the delay you see.
> 
> 
> -- 
> kind regards,
> 
> David Sommerseth
> 
> 
> > -----Original message-----
> >> From:Bill Maidment <[log in to unmask]>
> >> Sent: Saturday 21st January 2017 7:48
> >> To: David Sommerseth <[log in to unmask]>; [log in to unmask]
> >> Subject: RE: SL7.3RC2 shutdown slow
> >>
> >> David
> >> Thanks for the info. However, this only deals with booting. My issue is with shutdown.
> >> Your other email points to a shutdown diagnostic, so I'll try that, but I'm a bit wary of that not being a stable process.
> >>  
> >>  
> >> -----Original message-----
> >>> From:David Sommerseth <[log in to unmask]>
> >>> Sent: Saturday 21st January 2017 2:11
> >>> To: Bill Maidment <[log in to unmask]>; [log in to unmask]
> >>> Subject: Re: SL7.3RC2 shutdown slow
> >>>
> >>> On 20/01/17 09:11, Bill Maidment wrote:
> >>>> Update.....
> >>>>
> >>>> After shutting down several times everything seems to have settled
> >>>> down and there is no delay. Maybe I'm too impatient. Or something
> >>>> needed time to stabilize.
> >>>
> >>> When you experience such issues, systemd does have a good way to help
> >>> point fingers at why the boot process lags ...
> >>>
> >>>   # systemd-analyze blame
> >>>
> >>> Replace 'blame' with 'plot', and you'll get an SVG file with a graphical
> >>> presentation of the boot process, in which order unit files started,
> >>> when they started and how much time each of them needed.  Or use 'dot'
> >>> to get a similar view in the dot(1) format.
> >>>
> >>>
> >>> -- 
> >>> kind regards,
> >>>
> >>> David Sommerseth
> >>>
> >>>
> >>>> -----Original message-----
> >>>>> From:Bill Maidment <[log in to unmask]>
> >>>>> Sent: Friday 20th January 2017 17:58
> >>>>> To: [log in to unmask]
> >>>>> Subject: SL7.3RC2 shutdown slow
> >>>>>
> >>>>> Hi
> >>>>> I've created a new KVM guest using RC2 and no problems installing and updating from 7rolling, but rebooting is very slow.
> >>>>> I tried doing a shutdown and notice a 1min 30sec delay shutting down Dynamic System Tuning Daemon.
> >>>>> Is this expected behaviour on a new install?
> >>>>>
> >>>>> Cheers
> >>>>> Bill Maidment
> >>>>>
> >>>>>
> >>>
> >>>
> >>
> >>
> 
> 
>