Query on the Hardware Interrupts!!!

NTDEV
1

Hi all,

Is there any limit on the number of interrupts the NT 4.0 Single
processor machine can process (from the Operating system side)
We are facing a problem where we get lots interrupts and the we queue a
DPC for each interrupt
but DPC never gets called.
so the whole machine is hung up…
so can somebody suggest on how to debug these scenarios…

thanks in advance,

KIRAN MANDAVA,

2

First, you can only queue one DPC per device. This means that if you already
have one ISR requested DPC on the device queue if you request another one,
it will be lost unless your ISR places it on a queue that you manage in your
DPC. Note that you have to synchronize access to that queue with the Device
IRQL.

-----Original Message-----
From: Kiran Mandava [mailto:xxxxx@skystream.com]
Sent: Monday, July 24, 2000 4:15 PM
To: NT Developers Interest List
Subject: [ntdev] Query on the Hardware Interrupts!!!

Hi all,

Is there any limit on the number of interrupts the NT 4.0 Single
processor machine can process (from the Operating system side)
We are facing a problem where we get lots interrupts and the we
queue a
DPC for each interrupt
but DPC never gets called.
so the whole machine is hung up…
so can somebody suggest on how to debug these scenarios…

thanks in advance,

KIRAN MANDAVA,

You are currently subscribed to ntdev as: xxxxx@delphieng.com
To unsubscribe send a blank email to $subst(‘Email.Unsub’)

3

There isn’t a one-to-one relationship with interrupts and DPCs. If you get
an interrupt and queue up a DPC, then get another interrupt before the DPC
gets called,… at most only one DPC will get queued.

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> -----Original Message-----
> From: Kiran Mandava [mailto:xxxxx@skystream.com
mailto:xxxxx]
> Sent: Monday, July 24, 2000 6:15 PM
> To: NT Developers Interest List
> Subject: [ntdev] Query on the Hardware Interrupts!!!
>
>
> Hi all,
>
> Is there any limit on the number of interrupts the NT 4.0 Single
> processor machine can process (from the Operating system side)
> We are facing a problem where we get lots interrupts and
> the we queue a
> DPC for each interrupt
> but DPC never gets called.
> so the whole machine is hung up…
> so can somebody suggest on how to debug these scenarios…
>
> thanks in advance,
>
>
> KIRAN MANDAVA,
>
>
> —
> You are currently subscribed to ntdev as: Zeus@ti.com
> To unsubscribe send a blank email to $subst(‘Email.Unsub’)
></mailto:xxxxx>

4

>There isn’t a one-to-one relationship with interrupts and DPCs. If

you get an interrupt and queue up a DPC, then get another
interrupt before the DPC gets called,… at most only one DPC will

For instance - 56K modem causes about 1000 interrupts per second and only
~30 DPCs.

Max