Prevent IRQ sharing

Hello,
How can I programatically prevent a particular IRQ by being shared by
multiple devices?
TIA
Binu

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Binu K. Baby
Device Drivers Group, Network Systems & Technologies Pvt. Ltd. (NeST)
Phone: +91 471 527441 (Ext. 48), E-mail: xxxxx@nestec.net
Visit us at http://www.nesttech.com
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If you are referring to a PCI device on W2K, then you can’t. These
interrupts are shared. You will just have to live with everyone else on your
vector.

Mark Roddy
xxxxx@hollistech.com
www.hollistech.com
603 321 1032
WindowsNT Windows 2000 Consulting Services

-----Original Message-----
From: BINU K BABY [mailto:xxxxx@nestec.net]
Sent: Wednesday, March 21, 2001 2:57 AM
To: NT Developers Interest List
Subject: [ntdev] Prevent IRQ sharing

Hello,
How can I programatically prevent a particular IRQ by being shared by
multiple devices?
TIA
Binu

****************************************************************************
*************
Binu K. Baby
Device Drivers Group, Network Systems & Technologies Pvt. Ltd. (NeST)
Phone: +91 471 527441 (Ext. 48), E-mail: xxxxx@nestec.net
Visit us at http://www.nesttech.com
****************************************************************************
*************


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You *must* write the driver to support sharing, therefore I assume you are interested in performance.

You can reduce sharing by playing with the which slot the card is plugged into.

I believe the multiprocessor HAL uses the APIC differently than the uniprocessor version,
but I’m not sure if this affects the number of PCI interrupts used.

Some hardware platforms may have more capability in terms of spreading interrupts
out than the HAL exposes. Therefore for some applications (i.e., servers with
lots of devices and CPUs), a HAL change might be desirable.

At high interrupt rates, I have played games to avoid the extra PCI reads due to sharing
on particular hardware by looking at the cache-enabled shared memory to see if the device
“should be” interrupting (a couple clocks if its not), avoiding the hundreds of clocks for the PCI read.
I was able to improve performance by a couple percent just by doing this.
-DH

Dave Harvey, System Software Solutions, Inc.
617-964-7039, FAX 208-361-9395, xxxxx@syssoftsol.com, http://www.syssoftsol.com
Creators of RedunDisks - Robust RAID 1 for embedded systems.

----- Original Message -----
From: “Roddy, Mark”
To: “NT Developers Interest List”
Sent: Wednesday, March 21, 2001 8:43 AM
Subject: [ntdev] RE: Prevent IRQ sharing

> If you are referring to a PCI device on W2K, then you can’t. These
> interrupts are shared. You will just have to live with everyone else on your
> vector.
>
> Mark Roddy
> xxxxx@hollistech.com
> www.hollistech.com
> 603 321 1032
> WindowsNT Windows 2000 Consulting Services
>
>
>
> -----Original Message-----
> From: BINU K BABY [mailto:xxxxx@nestec.net]
> Sent: Wednesday, March 21, 2001 2:57 AM
> To: NT Developers Interest List
> Subject: [ntdev] Prevent IRQ sharing
>
>
> Hello,
> How can I programatically prevent a particular IRQ by being shared by
> multiple devices?
> TIA
> Binu
>
> ***************************************************************
>

> Binu K. Baby
> Device Drivers Group, Network Systems & Technologies Pvt. Ltd. (NeST)
> Phone: +91 471 527441 (Ext. 48), E-mail: xxxxx@nestec.net
> Visit us at http://www.nesttech.com
> ***************************************************************
>

>
>
> —
> You are currently subscribed to ntdev as: xxxxx@stratus.com
> To unsubscribe send a blank email to leave-ntdev-$subst(‘Recip.MemberIDChar’)@lists.osr.com
>
> —
> You are currently subscribed to ntdev as: xxxxx@syssoftsol.com
> To unsubscribe send a blank email to leave-ntdev-$subst(‘Recip.MemberIDChar’)@lists.osr.com


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