[Asterisk-Users] more then two wildcards in one machine

[Shoval Tomer]

Thanks for clearing this up.

> -----Original Message-----
> From: Kristian Kielhofner [mailto:kris at krisk.org]
> Sent: Thursday, December 09, 2004 1:50 AM
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Subject: Re: [Asterisk-Users] more then two wildcards in one machine
> 
> Matthew Boehm wrote:
> > The problem (from what I know) deals with IRQ interrupts. Each
digium
> card
> > must have a seperate IRQ and must be the only card on that IRQ. I
ran
> into a
> > problem plugging in just 1 digium card into each and every PCI slot
on
> our
> > Dell server and it was still sharing an IRQ with the ethernet card.
It
> wasnt
> > until I dissabled the usb, parallel port, serial port #2 and the
mouse
> that
> > it finally got its own irq.
> >
> > Mac's don't have IRQs. This is probably why it was so easy getting 4
> cards
> > into his mac.
> >
> > -Matthew
> 
> 
> Matthew (and everyone else),
> 
> http://www.microsoft.com/whdc/system/sysperf/apic.mspx
> 
> 	The problem is interrupts, not PCI slots.  As this article
explains,
> sharing interrupts adds a signifigant amount of latency to the
> interrupt, causing audio droupouts and other weird stuff to happen.
It
> is nothing specific to Digium hardware or Linux or anything like that.
> On a desktop running Windows (or any other OS) with a lot of devices
try
> to play back an MP3 and generate network, disk, and other I/O activity
> on a machine without APIC - the audio WILL skip.  Now imagine you are
> trying to drive 96+ T1 channels, ethernet boards and who know hom much
> else.  You can see where there might be a problem.
> 
> 	Apple Mac's have interrupts.  They just have a lot of them.  A
> modern
> Mac is very similar when compared to a modern x86 with an APIC.  Read
> more.
> 
> 	This is being mitigated on the x86 arhitecture by the APIC -
> Advanced
> Processor Interrupt Controller.  You can have more than one APIC in a
> machine, and each APIC has 24 IRQs.  Most new motherboards have at
least
> one APIC/processor.
> 
> Dell PowerEdge 2850 (dual Xeon):
> 
> ------------------------------------------------------------------
> ast1 etc # uname -a
> Linux ast1 2.6.9-pe2850a #2 SMP Fri Dec 3 09:23:03 CST 2004 i686
> Intel(R) Xeon(TM) CPU 3.00GHz GenuineIntel GNU/Linux
> ast1 etc # cat /proc/interrupts
>             CPU0       CPU1
>    0:    6184515         72    IO-APIC-edge  timer
>    1:          8          1    IO-APIC-edge  i8042
>    9:          0          0   IO-APIC-level  acpi
>   12:         65          1    IO-APIC-edge  i8042
>   14:         11          2    IO-APIC-edge  ide0
>   46:      19595          1   IO-APIC-level  megaraid
>   64:      66366          1   IO-APIC-level  eth0
>   65:      77045          1   IO-APIC-level  eth1
> 101:    6113521          1   IO-APIC-level  wctdm
> NMI:          1          0
> LOC:    6184694    6184698
> ERR:          0
> MIS:          0
> ast1 etc #
>
------------------------------------------------------------------------
-
> Apple Macintosh G4:
> 
>
------------------------------------------------------------------------
--
> [root at localhost root]# uname -a
> Linux localhost.localdomain 2.6.8-1.ydl.7 #1 Wed Sep 22 18:46:40 EDT
> 2004 ppc ppc ppc GNU/Linux
> [root at localhost root]# cat /proc/interrupts
>             CPU0
>   19:       4540   OpenPIC   Level     ide0
>   20:         12   OpenPIC   Level     ide1
>   25:        318   OpenPIC   Level     VIA-PMU
>   26:          0   OpenPIC   Level     keywest i2c
>   27:         35   OpenPIC   Level     ohci_hcd
>   28:         97   OpenPIC   Level     ohci_hcd
>   41:       1248   OpenPIC   Level     eth0
>   42:          0   OpenPIC   Level     keywest i2c
>   47:          0   OpenPIC   Level     GPIO1/ADB
>   54:   19036943   OpenPIC   Level     wctdm
>   55:          0   OpenPIC   Edge      NMI - XMON
>   63:          3   OpenPIC   Level     ohci1394
> BAD:          0
> [root at localhost root]#
>
------------------------------------------------------------------------
--
> -----
> 
> As you can see, on the Dell, the wctdm board has IRQ 101.  Waaaaayyyyy
> past good ol' 15.  On the Mac, it is at 54.  Still way beyond the
> standard x86 15 limit.
> 
> Now, if you are using an OS that can't do APIC on x86, or have a
> motherboard that has a mal-functioning APIC, you are out of luck and
> have to try to get them all to play nice.  I hope that this clears
> things up some.
> 
> --
> Kristian Kielhofner
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