Hello, I've been using a realtime kernel some time ago. I hadn't a very intensive use of it so I didn't even notice if its configuration was very right or wrong, it seemed fine, but I ended up uninstalling it and doing fine without. As of now I'm running Debian Jessie, and lately I've been trying the latest kernel Debian from their repos (currently, from wheezy-backports). However, JACK can't seem to get to work with realtime. Here is part of the log: 14:11:39.082 JACK démarre... 14:11:39.083 /usr/bin/jackd -r -dalsa -r44100 -p512 -n2 -D -Chw:Pro,0 -Phw:Pro,0 Cannot connect to server socket err = Aucun fichier ou dossier de ce type Cannot connect to server request channel jack server is not running or cannot be started 14:11:39.110 JACK a été démarrer avec le PID=3903. Cannot create RT messagebuffer thread: Operation not permitted (1) Retrying messagebuffer thread without RT scheduling Messagebuffer not realtime; consider enabling RT scheduling for user no message buffer overruns Cannot create RT messagebuffer thread: Operation not permitted (1) Retrying messagebuffer thread without RT scheduling Messagebuffer not realtime; consider enabling RT scheduling for user no message buffer overruns Gtk-Message: (for origin information, set GTK_DEBUG): failed to retrieve property `GtkRange::activate-slider' of type `gboolean' from rc file value "((GString*) 0x1cb8c40)" of type `GString' Cannot create RT messagebuffer thread: Operation not permitted (1) Retrying messagebuffer thread without RT scheduling Messagebuffer not realtime; consider enabling RT scheduling for user no message buffer overruns jackdmp 1.9.10 Here is the content of /etc/security/limits.d/audio.conf # Provided by the jackd package. # # Changes to this file will be preserved. # # If you want to enable/disable realtime permissions, run # # dpkg-reconfigure -p high jackd @audio - rtprio 95 @audio - memlock unlimited #@audio - nice -19 Note: the dpkg-reconfigure is "wrong" since in my case I use "jackd2". Content of /etc/default/rtirq: (...) # IRQ thread service names # (space separated list, from higher to lower priority). RTIRQ_NAME_LIST="rtc snd usb i8042" # Highest priority. RTIRQ_PRIO_HIGH=90 # Priority decrease step. RTIRQ_PRIO_DECR=5 # Lowest priority. RTIRQ_PRIO_LOW=51 # Whether to reset all IRQ threads to SCHED_OTHER. RTIRQ_RESET_ALL=0 # On kernel configurations that support it, # which services should be NOT threaded # (space separated list). RTIRQ_NON_THREADED="rtc snd" # Process names which will be forced to the # highest realtime priority range (99-91) # (space separated list, from highest to lower priority). # RTIRQ_HIGH_LIST="timer" Results of a few commands, $ uname -a Linux cacacomp 3.12-1-rt-amd64 #1 SMP PREEMPT RT Debian 3.12.9-1+rt1 (2014-02-20) x86_64 GNU/Linux $ cat /boot/config-3.12-1-rt-amd64 | grep PREEMPT CONFIG_TREE_PREEMPT_RCU=y CONFIG_PREEMPT_RCU=y CONFIG_PREEMPT_NOTIFIERS=y CONFIG_PREEMPT=y CONFIG_PREEMPT_RT_BASE=y CONFIG_HAVE_PREEMPT_LAZY=y CONFIG_PREEMPT_LAZY=y # CONFIG_PREEMPT_NONE is not set # CONFIG_PREEMPT_VOLUNTARY is not set # CONFIG_PREEMPT__LL is not set # CONFIG_PREEMPT_RTB is not set CONFIG_PREEMPT_RT_FULL=y CONFIG_PREEMPT_COUNT=y CONFIG_DEBUG_PREEMPT=y # CONFIG_PREEMPT_TRACER is not set $ cat /boot/config-3.12-1-rt-amd64 | grep _RT_ CONFIG_RT_MUTEXES=y CONFIG_PREEMPT_RT_BASE=y CONFIG_PREEMPT_RT_FULL=y # CONFIG_DEBUG_RT_MUTEXES is not set # CONFIG_RT_MUTEX_TESTER is not set # lsusb Bus 002 Device 003: ID 5986:0315 Acer, Inc Bus 002 Device 004: ID 0763:2012 Midiman M-Audio Fast Track Pro Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub => I have a M-Audio Fast Track Pro USB card. # grep CONFIG_RT_GROUP_SCHED /boot/config-3.12-1-rt-amd64 # (empty, this string isn't in my kernel config file) I realize I didn't tick "realtime" in qjackctl, so I start it again but JACK log is the same: 15:12:46.782 JACK démarre... 15:12:46.783 /usr/bin/jackd -v -dalsa -r44100 -p512 -n2 -D -Chw:Pro,0 -Phw:Pro,0 Cannot connect to server socket err = Aucun fichier ou dossier de ce type Cannot connect to server request channel jack server is not running or cannot be started 15:12:46.797 JACK a été démarrer avec le PID=7290. Cannot create RT messagebuffer thread: Operation not permitted (1) Retrying messagebuffer thread without RT scheduling Messagebuffer not realtime; consider enabling RT scheduling for user no message buffer overruns Cannot create RT messagebuffer thread: Operation not permitted (1) Retrying messagebuffer thread without RT scheduling Messagebuffer not realtime; consider enabling RT scheduling for user no message buffer overruns Cannot create RT messagebuffer thread: Operation not permitted (1) Retrying messagebuffer thread without RT scheduling Messagebuffer not realtime; consider enabling RT scheduling for user no message buffer overruns jackdmp 1.9.10 ... There are very few references of this specific error message I found on the web, but none seem to be related with my case. # service rtirq status PID CLS RTPRIO NI PRI %CPU STAT COMMAND 45 FF 90 - 130 0.0 S irq/8-rtc0 556 FF 85 - 125 0.0 S irq/43-snd_hda_ 429 FF 80 - 120 0.0 S irq/16-ehci_hcd 430 FF 79 - 119 5.3 S irq/23-ehci_hcd 44 FF 75 - 115 0.0 S irq/1-i8042 43 FF 74 - 114 0.6 S irq/12-i8042 30 FF 50 - 90 0.0 S irq/9-acpi 128 FF 50 - 90 0.0 S irq/40-ahci 424 FF 50 - 90 0.0 S irq/41-mei_me 431 FF 50 - 90 0.0 S irq/16-mmc0 456 FF 50 - 90 0.6 S irq/18-rtl_pci 499 FF 50 - 90 0.0 S irq/16-jmb38x_m 522 FF 50 - 90 0.0 S irq/42-i915 2675 FF 50 - 90 0.0 S irq/44-eth0 3 FF 1 - 41 0.0 S ksoftirqd/0 19 FF 1 - 41 0.0 S ksoftirqd/1 $ ./realTimeConfigQuickScan.pl == GUI-enabled checks == Checking if you are root... no - good Checking filesystem 'noatime' parameter... not found - warning /boot does not have the 'noatime' parameter set For more information, see http://wiki.linuxaudio.org/wiki/system_configuration#filesystems Checking CPU Governors... CPU 0: 'powersave' CPU 1: 'powersave' - not good Set CPU Governors to 'performance' with 'cpufreq-set -c <cpunr> -g performance' See also: http://linuxmusicians.com/viewtopic.php?f=27&t=844 Checking swappiness... 60 - not good ** vm.swappiness is larger than 10 set it with '/sbin/sysctl -w vm.swappiness=10' See also: http://linuxmusicians.com/viewtopic.php?f=27&t=452&start=30#p8916 Checking for resource-intensive background processes... none found - good Checking checking sysctl inotify max_user_watches... < 524288 - not good increase max_user_watches by adding 'fs.inotify.max_user_watches = 524288' to /etc/sysctl.conf and rebooting For more information, see http://wiki.linuxaudio.org/wiki/system_configuration#sysctlconf Checking access to the high precision event timer... readable - good Checking access to the real-time clock... readable - good Checking whether you're in the 'audio' group... yes - good Checking for multiple 'audio' groups... no - good chrt: failed to set pid 0's policy: Opération non permise Checking the ability to prioritize processes with chrt... no - not good Could not assign a 80 rtprio value. Set up limits.conf. For more information, see http://wiki.linuxaudio.org/wiki/system_configuration#limitsconfaudioconf Checking kernel support for high resolution timers... found - good Kernel with Real-Time Preemption... found - good Checking if kernel system timer is set to 1000 hz... not found - not good Try setting CONFIG_HZ to 1000 Checking kernel support for tickless timer... not found - not good Try enabling tickless timer support (CONFIG_NO_HZ) == Other checks == Checking filesystem types... ok. not found. ** Warning: no tmpfs partition mounted on /tmp For more information, see: - http://wiki.linuxaudio.org/wiki/system_configuration#tmpfs - http://lowlatency.linuxaudio.org ** Set $SOUND_CARD_IRQ to the IRQ of your soundcard to enable more checks. Find your sound card's IRQ by looking at '/proc/interrupts' and lspci. So, I'd like to know what prevents Jack from getting RT priorities. And that's about all. I'm stuck. Hope you guys see where is the problem more than I do and can point my to some direction. Regards, 01