Re: [Qtractor-devel] System lock-up on MIDI clocking

[Ralf M. <ral...@al...>]

On Tue, 2014-08-12 at 21:29 +0200, Ralf Mardorf wrote:
> On Tue, 2014-08-12 at 18:49 +0200, Holger Marzen wrote:
> > On Mon, 11 Aug 2014, oli_kester wrote:
> > 
> > > Thanks for the responses Ralf, they've pointed me in the right direction :)
> > > 
> > > What solved this for me was setting the queue timer resolution to
> > > "system timer (1000Hz)". When I switch to "HR timer (1000000000Hz)" ,
> > > which I presume is the default, the system locks up after a short play
> > > time - even in the first bar! I'm not surprised this is what was
> > > causing issues - a billion Hz is gigantic! Surprised any computer can
> > > send MIDI signals that fast. 
> > 
> > This seems to be a still existent ALSA problem in the kernel. It happens
> > with Rosegarden, too.
> 
> No problem here. HPET and Qtractor do work. IIRC in the past, I might
> confuse it with another issue, there was the need to launch Qtractor
> with the session file, IOW
> 
> qtractor /path/file.qtr
> 
> IIRC when not doing this there was an error, "HPET already in use" or
> similar. Again, I might confuse it with another issue. Btw. I start my
> sessions with a script IOW I still launch Qtractor with the .qtr file.
> 
> JFTR I don't use jackd with HPET/HR Timer, perhaps there are only issues
> when using jackd and the sequencer with HPET?! Another issue might be
> caused by the kernel tickless options (NO_HZ).
> 
> [rocketmouse@archlinux ~]$ zgrep HZ /proc/config.gz
> CONFIG_HZ_PERIODIC=y
> # CONFIG_NO_HZ_IDLE is not set
> # CONFIG_NO_HZ_FULL is not set
> # CONFIG_NO_HZ is not set
> # CONFIG_HZ_100 is not set
> # CONFIG_HZ_250 is not set
> # CONFIG_HZ_300 is not set
> CONFIG_HZ_1000=y
> CONFIG_HZ=1000
> CONFIG_MACHZ_WDT=m
> [rocketmouse@archlinux ~]$ uname -rm
> 3.10.47-rt50-1-rt-lts x86_64
> 
> JFTR this 3.10 kernel with patch _50_ is the one and only
> kernel > 3.8 PREEMPT RT that doesn't lock my machine.
> Kernels <= 3.8 PREEMPT RT are ok, kernels >= 3.8 PREEMPT RT usually lock
          <= 3.8 is correct, but  :D       ^^^ > 3.8 ;), not >= ;)
> my machine.