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Nt and device interrupts

OSR_Community_UserOSR_Community_User Member Posts: 110,217
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?

Comments

  • OSR_Community_UserOSR_Community_User Member Posts: 110,217
    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')
  • OSR_Community_UserOSR_Community_User Member Posts: 110,217
    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_UserOSR_Community_User Member Posts: 110,217
    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]
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