[LAU] IRQ and RT question

Ralf Mardorf ralf.mardorf at alice-dsl.net
Sun Dec 9 10:18:17 UTC 2012


On Thu, 2012-12-06 at 10:49 -0600, Aaron Krister Johnson wrote:
> IRQ settings

My sound card (snd_hdsp) does share IRQ 18 with the graphics (radeon),
when using older kernels, with newer kernel the graphics gets IRQ 43.

### Old kernel Ubuntu Studio Precise:

spinymouse at precise:~$ service rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND	
   93 FF      90   - 130  0.0 S    irq/8-rtc0	
   86 FF      85   - 125  0.0 S    irq/18-ohci_hcd	
   91 FF      84   - 124  0.0 S    irq/18-ohci_hcd	
  715 FF      83   - 123  0.0 S    irq/18-radeon	
  765 FF      82   - 122  0.0 S    irq/18-snd_hdsp	
  781 FF      70   - 110  0.0 S    irq/20-snd_ice1	
  787 FF      69   - 109  0.0 S    irq/21-snd_ice1	
   80 FF      60   - 100  0.0 S    irq/19-ehci_hcd	
   82 FF      60   - 100  0.0 S    irq/16-ohci_hcd	
   84 FF      59   -  99  0.2 S    irq/17-ohci_hcd	
   88 FF      58   -  98  0.0 S    irq/17-ohci_hcd	
   92 FF      55   -  95  0.0 S    irq/1-i8042	
   20 FF      50   -  90  0.0 S    irq/9-acpi	
   68 FF      50   -  90  0.4 S    irq/22-ahci	
  257 FF      50   -  90  0.0 S    irq/14-pata_ati	
  262 FF      50   -  90  0.0 S    irq/15-pata_ati	
  296 FF      50   -  90  0.1 S    irq/22-firewire	
  590 FF      50   -  90  0.0 S    irq/7-parport0	
 1052 FF      50   -  90  0.0 S    irq/42-eth0	
    3 TS       -   0  19  0.2 S    ksoftirqd/0	
    9 TS       -   0  19  0.2 S    ksoftirqd/1	

spinymouse at precise:~$ uname -r
3.2.0-23-lowlatency

### New kernels Ubuntu Quantal:

spinymouse at q:/mnt/music/quantal/01song$ service rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND	
   60 FF      90   - 130  0.0 S    irq/8-rtc0	
  619 FF      85   - 125  0.0 S    irq/20-snd_ice1	
  621 FF      85   - 125  0.0 S    irq/18-snd_hdsp	
  622 FF      85   - 125  0.0 S    irq/21-snd_ice1	
   50 FF      80   - 120  0.0 S    irq/19-ehci_hcd	
   53 FF      80   - 120  0.0 S    irq/16-ohci_hcd	
   54 FF      79   - 119  0.0 S    irq/17-ohci_hcd	
   56 FF      78   - 118  0.0 S    irq/18-ohci_hcd	
   57 FF      78   - 118  0.0 S    irq/17-ohci_hcd	
   58 FF      77   - 117  0.0 S    irq/18-ohci_hcd	
   59 FF      75   - 115  0.0 S    irq/1-i8042	
   21 FF      50   -  90  0.0 S    irq/9-acpi	
   43 FF      50   -  90  0.7 S    irq/22-ahci	
  225 FF      50   -  90  0.0 S    irq/14-pata_ati	
  226 FF      50   -  90  0.0 S    irq/15-pata_ati	
  266 FF      50   -  90  0.2 S    irq/22-firewire	
  490 FF      50   -  90  0.0 S    irq/7-parport0	
  530 FF      50   -  90  0.0 S    irq/43-radeon	
  955 FF      50   -  90  0.0 S    irq/42-eth0	
    3 TS       -   0  19  0.4 S    ksoftirqd/0	
   10 TS       -   0  19  0.4 S    ksoftirqd/1	

spinymouse at q:/mnt/music/quantal/01song$ uname -r
3.5.0-18-lowlatency

spinymouse at q:/mnt/music/quantal/01song$ service rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND	
   62 FF      90   - 130  0.0 S    irq/8-rtc0	
  781 FF      85   - 125  0.0 S    irq/18-snd_hdsp	
  820 FF      85   - 125  0.0 S    irq/20-snd_ice1	
  841 FF      85   - 125  0.0 S    irq/21-snd_ice1	
   54 FF      80   - 120  0.0 S    irq/19-ehci_hcd	
   55 FF      80   - 120  0.0 S    irq/16-ohci_hcd	
   56 FF      79   - 119  0.0 S    irq/17-ohci_hcd	
   58 FF      78   - 118  0.0 S    irq/18-ohci_hcd	
   59 FF      78   - 118  0.0 S    irq/17-ohci_hcd	
   60 FF      77   - 117  0.0 S    irq/18-ohci_hcd	
   61 FF      75   - 115  0.0 S    irq/1-i8042	
   24 FF      50   -  90  0.0 S    irq/9-acpi	
   46 FF      50   -  90  0.8 S    irq/22-ahci	
  212 FF      50   -  90  0.0 S    irq/14-pata_ati	
  213 FF      50   -  90  0.0 S    irq/15-pata_ati	
  286 FF      50   -  90  0.2 S    irq/22-firewire	
  649 FF      50   -  90  0.0 S    irq/7-parport0	
  757 FF      50   -  90  0.1 S    irq/43-radeon	
  988 FF      50   -  90  0.0 S    irq/42-eth0	
    3 FF       1   -  41  0.4 S    ksoftirqd/0	
   15 FF       1   -  41  0.4 S    ksoftirqd/1	

spinymouse at q:/mnt/music/quantal/01song$ uname -r
3.6.5-rt14

The order of the audio cards is fixed, I wonder why the hdsp and ice
cards get different IRQ orders, but with equal priorities. I'll
replace ...

spinymouse at q:/mnt/music/quantal/01song$ grep RTIRQ_NAME_LIST /etc/default/rtirq
RTIRQ_NAME_LIST="rtc snd usb i8042"

... by "rtc snd_hdsp snd_ice1 snd usb i8042" or similar. I suspect the
priorities still will be equal. Sometimes the rtirq packages doesn't fit
to the packaged kernel version.

To get rid of other stuff sharing the IRQ with the graphics, I unbind
some devices by a script:

spinymouse at q:/mnt/music/quantal/01song$ sudo bash tuning
bluetooth stop/waiting
cups stop/waiting
##############################
$ /etc/init.d/rtirq status       

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND	
   62 FF      90   - 130  0.0 S    irq/8-rtc0	
  781 FF      85   - 125  0.0 S    irq/18-snd_hdsp	
   54 FF      80   - 120  0.0 S    irq/19-ehci_hcd	
   55 FF      80   - 120  0.0 S    irq/16-ohci_hcd	
   56 FF      79   - 119  0.1 S    irq/17-ohci_hcd	
   59 FF      78   - 118  0.0 S    irq/17-ohci_hcd	
   61 FF      75   - 115  0.0 S    irq/1-i8042	
   24 FF      50   -  90  0.0 S    irq/9-acpi	
   46 FF      50   -  90  0.0 S    irq/22-ahci	
  212 FF      50   -  90  0.0 S    irq/14-pata_ati	
  213 FF      50   -  90  0.0 S    irq/15-pata_ati	
  649 FF      50   -  90  0.0 S    irq/7-parport0	
  757 FF      50   -  90  0.0 S    irq/43-radeon	
  988 FF      50   -  90  0.0 S    irq/42-eth0	
    3 FF       1   -  41  0.1 S    ksoftirqd/0	
   15 FF       1   -  41  0.1 S    ksoftirqd/1	

$ grep 18: /proc/interrupts
 18:          0          4   IO-APIC-fasteoi   snd_hdspm

Sun Dec 9 10:53:04 CET 2012 - 3.6.5-rt14 - Ubuntu 12.10 \n \l

spinymouse at q:/mnt/music/quantal/01song$ cat tuning
#!/bin/bash

# sudo bash tuning - Ubuntu Studio Quantal
# 2012/Nov/04

### http://www.mythtv.org/wiki/PCI_Latency
### http://wiki.linuxmusicians.com/doku.php?id=system_configuration#pci_bus_latency

### Bluetooth
service bluetooth stop

### Network
#service network-manager stop
#service networking stop # does cause serious issues
#modprobe -r r8169 # Ethernet NIC driver

### TerraTec EWX 24/96
modprobe -r snd_ice1712

### Others
modprobe -r firewire-ohci
modprobe -r firewire_core
service cups stop
modprobe -r ppdev # parallel port
modprobe -r lp    # printer

### Unbinding devices
echo -n "0000:00:13.2" > /sys/bus/pci/drivers/ohci_hcd/unbind
echo -n "0000:00:13.4" > /sys/bus/pci/drivers/ohci_hcd/unbind

### Log file
l="log/tuning.log"
#echo "$ lspci -v                       "  > $l
#lspci -v                                 >> $l
#echo                                     >> $l
echo "$ /etc/init.d/rtirq status       "  > $l
/etc/init.d/rtirq status                 >> $l
echo "$ grep 18: /proc/interrupts"       >> $l
grep 18: /proc/interrupts                >> $l
echo                                     >> $l
echo -n $(date)" - "$(uname -r)" - "     >> $l
cat /etc/issue                           >> $l
echo "##############################" ; cat $l

exit 0

See the links in the script for more information.

Hth,
Ralf




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