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

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

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
my machine.