Nt and device interrupts

OSR_Community_User

Hi
Can anybody tell me about NT and device interrupts? How fast I can program my
ISR service start time? What is a latency when my device interrupting and my
driver start to service it. Now my driver start service it when time elapsed
148 us. That sounds very long time. Are there ways to shorten this time?

OSR_Community_User

probably no......because this will totally depend on the Current state of
Windows NT .You could not do anything because the control comes to you
after 140 us (as you said). So even if you wanted to play with IRQLs you
can only do that after 140 us.
But i still feel you can find the solution In registry of Windows NT. It's
just my guess but i can say that it would not be that bad.As you can vary
the page table size and available physical memory size using registry you
might also have some control over the device interrupts.

Thanks
Ajitabh

Ajitabh Prakash
Sr.Software Engineer
Future Software
480/481 Nandnam,Chennai

-----Original Message-----
From: [email protected] [SMTP:[email protected]]
Sent: Monday, April 17, 2000 4:53 PM
To: NT Developers Interest List
Subject: [ntdev] Nt and device interrupts

Hi
Can anybody tell me about NT and device interrupts? How fast I can program
my
ISR service start time? What is a latency when my device interrupting and
my
driver start to service it. Now my driver start service it when time
elapsed
148 us. That sounds very long time. Are there ways to shorten this time?



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OSR_Community_User

The only registry thing one can do is to adjust the order in which your
driver is loaded. This might get you a different IRQL (on some systems on
some busses) and/or it might change your driver's relative order in a linked
list of ISRs sharing an interrupt.

Otherwise, latency is what it is. NT is not doing anything particularly
hideous with respect to getting from the interrupt event to the first driver
isr associated with an interrupt.

> -----Original Message-----
> From: Ajitabh Prakash [mailto:[email protected]]
> Sent: Monday, April 17, 2000 6:45 AM
> To: NT Developers Interest List
> Subject: [ntdev] RE: Nt and device interrupts
>
>
> probably no......because this will totally depend on the
> Current state of
> Windows NT .You could not do anything because the control
> comes to you
> after 140 us (as you said). So even if you wanted to play
> with IRQLs you
> can only do that after 140 us.
> But i still feel you can find the solution In registry
> of Windows NT. It's
> just my guess but i can say that it would not be that bad.As
> you can vary
> the page table size and available physical memory size using
> registry you
> might also have some control over the device interrupts.
>
> Thanks
> Ajitabh
>
> Ajitabh Prakash
> Sr.Software Engineer
> Future Software
> 480/481 Nandnam,Chennai
>
> -----Original Message-----
> From: [email protected] [SMTP:[email protected]]
> Sent: Monday, April 17, 2000 4:53 PM
> To: NT Developers Interest List
> Subject: [ntdev] Nt and device interrupts
>
> Hi
> Can anybody tell me about NT and device interrupts? How fast
> I can program
> my
> ISR service start time? What is a latency when my device
> interrupting and
> my
> driver start to service it. Now my driver start service it when time
> elapsed
> 148 us. That sounds very long time. Are there ways to shorten
> this time?
>
>
>
> ---
> You are currently subscribed to ntdev as: [email protected]
> To unsubscribe send a blank email to $subst('Email.Unsub')
>
>
> ---
> You are currently subscribed to ntdev as: [email protected]
> To unsubscribe send a blank email to $subst('Email.Unsub')
>

OSR_Community_User

You may be interested in the following WinHEC presentation which discusses
various Windows NT and 9x latencies (hardware interrupt, DPC, etc.). You
will need PowerPoint to view it.

http://www.microsoft.com/winhec/presents/audio/audio2/audio2.pps

- Matt


From: <[email protected]>
Sent: Monday, April 17, 2000 7:22 AM


> Hi
> Can anybody tell me about NT and device interrupts? How fast I can
program my
> ISR service start time? What is a latency when my device interrupting and
my
> driver start to service it. Now my driver start service it when time
elapsed
> 148 us. That sounds very long time. Are there ways to shorten this time?

[snip]