[linux-audio-user] Tuning Jack: Please help me prioritize IRQ 10

[Rick Wright]

Joe Hartley wrote:

>This has been a very timely discussion.  I just got my son a new mobo, CPU
>and RAM, and he's been having a lot of trouble using jack, ardour and hydrogen
>until I followed the advice here and tuned his machine up.  Thanks all!
>
>On Sat, 20 Jan 2007 12:21:58 -0500
>Rick Wright <riwright at vt.edu> wrote:
>  
>
>>Thus, your command should be something like :
>>
>>/usr/bin/chrt -f -p 90 `pidof "IRQ 10"`
>>    
>>
>
>Here's a novel twist on all of this:  my sound and video cards don't seem
>to exist on my FC5 system, so I can't run this command!
>
>For example, my audio card is a Delta 1010.  lspci -v shows it:
>02:0b.0 Multimedia audio controller: VIA Technologies Inc. ICE1712 [Envy24] PCI Multi-Channel I/O Controller (rev 02)
>        Subsystem: VIA Technologies Inc. M-Audio Delta 1010
>        Flags: bus master, medium devsel, latency 64, IRQ 11
>        I/O ports at df80 [size=32]
>        I/O ports at dfa0 [size=16]
>        I/O ports at df60 [size=16]
>        I/O ports at df00 [size=64]
>        Capabilities: [80] Power Management version 1
>
>However, it's not in /proc/interrupts, and trying to use chrt as shown
>above fails:
>[root at xtc ~]# cat /proc/interrupts 
>           CPU0       CPU1       
>  0:      67992    2883426  IO-APIC-edge   [........N/  0]  pit
>  1:          8          0  IO-APIC-edge   [........./  0]  i8042
>  8:          1          0  IO-APIC-edge   [........./  0]  rtc
>  9:          0          1  IO-APIC-level  [........./  0]  acpi
> 12:         96          0  IO-APIC-edge   [........./  0]  i8042
> 14:       6779         89  IO-APIC-edge   [........./  2]  ide0
> 15:      28172       6252  IO-APIC-edge   [........./  2]  ide1
> 17:          2          0  IO-APIC-level  [........./  0]  ehci_hcd:usb1
> 18:         31          0  IO-APIC-level  [........./  0]  uhci_hcd:usb2
> 19:       1276          0  IO-APIC-level  [........./  0]  skge
>NMI:          0          0 
>LOC:    2951050    2954633 
>ERR:          0
>MIS:          0
>[root at xtc ~]# chrt -f -p 82 `pidof "IRQ 11"`
>sched_getscheduler: No such process
>failed to get pid 82's policy
>
>Hmmm, where's the process for IRQ 11??
>
>  
>
You can check for the pid with:

ps -Leo pid,pri,rtprio,cmd | grep IRQ

The first column is the pid, the third is the rtprio, which is what gets 
set by the "chrt" command I posted previously.  This is a good check 
that you are able to set the "rtprio" value.

Once you have that pid, do:

/usr/bin/chrt -f -p 82 <pid>

The back-ticks and quotes are only required when this command is put in 
a script.

>[root at xtc ~]# ps -ef | grep IRQ
>root        33    27  0 15:28 ?        00:00:00 [IRQ 9]
>root       249    27  0 15:28 ?        00:00:00 [IRQ 8]
>root       268    27  0 15:28 ?        00:00:00 [IRQ 12]
>root       296    27  0 15:28 ?        00:00:00 [IRQ 14]
>root       299    27  0 15:28 ?        00:00:00 [IRQ 15]
>root       350    27  0 15:28 ?        00:00:00 [IRQ 1]
>root       838    27  0 15:28 ?        00:00:00 [IRQ 17]
>root       860    27  0 15:28 ?        00:00:00 [IRQ 18]
>root       897    27  0 15:28 ?        00:00:00 [IRQ 19]
>root      1133    27  0 15:28 ?        00:00:00 [IRQ 6]
>
>I'm really baffled here!  Has anyone seen this?  My video card (listed
>as having IRQ 18) is equally missing in action as well.  Thanks for any
>clues sent this way.
>
>  
>