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 > >>>>> > >>>>> > >>> > >>> > >> > >> > > >