Re: [LAU] IRQ and RT question

From: Ralf Mardorf <ralf.mardorf@email-addr-hidden-dsl.net>
Date: Sun Dec 09 2012 - 12:18:17 EET

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@email-addr-hidden:~$ 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@email-addr-hidden:~$ uname -r
3.2.0-23-lowlatency

### New kernels Ubuntu Quantal:

spinymouse@email-addr-hidden:/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@email-addr-hidden:/mnt/music/quantal/01song$ uname -r
3.5.0-18-lowlatency

spinymouse@email-addr-hidden:/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@email-addr-hidden:/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@email-addr-hidden:/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@email-addr-hidden:/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@email-addr-hidden:/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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Received on Sun Dec 9 12:15:02 2012

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