[LAU] Something interesting about kernel 3.6.5-rt14

[Ralf Mardorf]

On Sat, 03 Nov 2012 11:32:21 +0100
Florian Paul Schmidt <mista.tapas at gmx.net> wrote:

> On 11/03/2012 10:40 AM, Ralf Mardorf wrote:
> > I noticed something interesting about kernel 3.6.5-rt14.
> 
> [..]
> 
> > Unfortunately it didn't solve xrun issues for the RME card. However,
> > the kernel does switch to another IRQ for the graphics, for all
> > other kernels on different distros, the graphics always gets IRQ18,
> > also if I switch the integrated ATI with a Nvidia.
> >
> 
> Hi, this is a long shot, but you might play around with the PCI bus 
> latency settings for different devices.. I.e. turn them down from the 
> default value and see if it helps at all. I'm no expert in this, so
> make sure to read up on the subject.
> 
> http://www.mythtv.org/wiki/PCI_Latency
> 
> Maybe some device (most probably a GPU or a NIC) holds on to the PCI
> bus for too long..
> 
> Flo

Thank you Flo :)

if I remove all USB stuff I still see irq/18-ohci_hcd [1].

Regards,
Ralf

[1]
$ top

2583 spinymou  20   0 1155m 310m 107m S   9.3  8.4   3:09.87
 qtractor
2827 spinymou  20   0  392m  47m  21m S   1.7  1.3   0:05.03
 plugin-containe
2562 spinymou  20   0  275m  89m  82m S   1.3  2.4 0:27.17
 jackd
15 root      -2   0     0    0    0 S   1.0  0.0 0:04.39
 ksoftirqd/1
1264 root      20   0  150m  36m  14m S   1.0 1.0   1:05.48
 Xorg
2577 spinymou  20   0  536m 110m 100m S   1.0 3.0   0:10.23
 qjackctl.real
2785 spinymou  20   0  922m 139m  43m S 0.7  3.8 0:37.66
 firefox
58 root     -79   0     0    0    0 S 0.3  0.0 0:02.06
 irq/18-ohci_hcd
60 root     -78   0     0    0    0 S   0.3 0.0   0:03.43
 irq/18-ohci_hcd
849 root     -86   0     0 0    0 S 0.3  0.0 0:05.95
 irq/18-snd_hdsp
2159 spinymou  20   0 163m  14m   9m S   0.3 0.4 0:08.91
 panel-25-weathe
2487 spinymou 20   0  476m  18m 13m S 0.3  0.5 0:04.61
 xfce4-terminal
1 root      20   0 24432 2320 1272 S   0.0 0.1   0:01.27
init

spinymouse at qrc:~$ cat /proc/interrupts | grep 18
 18:          0     752885   IO-APIC-fasteoi   ohci_hcd:usb4,
                             ohci_hcd:usb6, snd_hdspm

spinymouse at qrc:~$ /etc/init.d/rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND	
   62 FF      90   - 130  0.0 S    irq/8-rtc0	
  849 FF      85   - 125  0.1 S    irq/18-snd_hdsp	
  908 FF      85   - 125  0.0 S    irq/20-snd_ice1	
  911 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  0.0 S    irq/22-ahci	
  214 FF      50   -  90  0.0 S    irq/14-pata_ati	
  215 FF      50   -  90  0.0 S    irq/15-pata_ati	
  301 FF      50   -  90  0.0 S    irq/22-firewire	
  720 FF      50   -  90  0.0 S    irq/7-parport0	
  727 FF      50   -  90  0.0 S    irq/43-radeon	
 1111 FF      50   -  90  0.0 S    irq/42-eth0	
    3 FF       1   -  41  0.3 S    ksoftirqd/0	
   15 FF       1   -  41  0.1 S    ksoftirqd/1