| Re: [proaudio] trouble emerging museseq |
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Le Thu, 18 May 2006 15:23:45 -0700,
Robert Persson <ireneshusband@xxxxxxxxxxx> a écrit :
> First of all, thanks for a very detailed and informative reply.
>
> On Thursday 18 May 2006 02:44 Dominique Michel was like:
> > RT-kernel are very sensitive to bad hardware configuration. IRQ can be
> > a big source of problem. You must be sure at you don't share some IRQ.
> > # cat /proc/interrupts
>
> >The most important is the sound and video.
>
> Here are my interrupts at the moment (the 2 cpus are actually a single
> hyperthreaded P4):
>
> CPU0 CPU1
> 0: 111983 0 IO-APIC-edge timer
> 1: 779 0 IO-APIC-edge i8042
> 8: 2 0 IO-APIC-edge rtc
> 9: 1 0 IO-APIC-level acpi
> 12: 19742 0 IO-APIC-edge i8042
> 14: 18008 0 IO-APIC-edge ide0
> 15: 622 0 IO-APIC-edge ide1
> 16: 24166 0 IO-APIC-level SysKonnect SK-98xx, ohci1394
> 17: 0 0 IO-APIC-level uhci_hcd:usb4
> 18: 81 0 IO-APIC-level ehci_hcd:usb1
> 19: 26052 0 IO-APIC-level uhci_hcd:usb2, uhci_hcd:usb5, \
> fglrx
> 20: 0 0 IO-APIC-level uhci_hcd:usb3
> 21: 0 0 IO-APIC-level EMU10K1
> 22: 0 0 IO-APIC-level Intel ICH5
> NMI: 0 0
> LOC: 111921 111899
> ERR: 0
> MIS: 0
>
> Obviously interrupt 19 is problematic because of the video driver (and it
> might explain some other odd behaviour as well). Should I be worried about
> any of the other interrupts?
No, I don't think so.
>
> And is changing them simply a matter of cmos settings, or do I need to do
> something in Linux?
>
If you can do it in the bios setting, it will just work out of the box. If not, you must try to move some cards from slot to slot, but maybe your graphic card is an agp, and you cannot do that. In some cases (at least nvidia), it is possible to not use the 3D hardware acceleration with the graphic card (if you don't need it) and to win an IRQ.
It is 2 kind of IRQ, hard and soft. We are dealing here with hardware IRQ and the only possible way to change them are by moving or removing the cards, and with the bios setting. Maybe at it is some way to tell the kernel to do the job of the bios and reprogram the IRQs in the PIC or APIC (APIC: Advanced Programable Interrupts Controller, it is in the silicium on the motherboard), but I don't know how. I know at it is some boot options for that. If interrested, you must RTFM the kernel doc.
Software IRQs are another thing that have to do with thread priority and such things. It is both the kernel and the apps that use and control it.
>
> > But in your case, I think at 512 MB RAM is too little to do serious audio
> > work. It is what was in my box, and I added 1GB and many problems as
> > intermitant noises was gone. I recommand for an audio workstation to have
> > the same hardware as a graphic station, high tech motherboard, huge ram
> > memory, but with simpler graphic card (less noise footprint), better sound
> > card (it is what we want) and better hdd system (a must for multitrack
> > recording).
>
> I too have 512MB ram, but I rarely see swap usage go above zero in Gnome
> System Monitor. Do you still think that RAM would be an issue for me too?
It depend of what you do with your system. If it work well, it is just to use it.
>
> > You must be sure at jack is using tmpfs (USE jack-tmpfs). Check in fstab at
> > you have: none /dev/shm tmpfs nodev,nosuid,noexec 0
> > 0 Otherwise, jackd will use the hdd to do its work, and it can be a hudge
> > amount of data. tmpfs will use RAM but the amount of data will remain the
> > same, it will work faster and with less noise.
>
> Mine reads:
> none /dev/shm tmpfs defaults 0 0
> Do I need to explicitly state nodev,nosuid,noexec?
I don't remember why I put this. If it work well, you have no raison to change it.
>
> All the best
> Robert
Cheers,
Dominique