2009-01-20 17:38:09

by linux

[permalink] [raw]
Subject: disabling interupts

Please advise if this question is OT. (If so, where can I post it or
read more about said topic?)

I have an application that grabs frames from a frame grabber. It is
dropping frames, sometimes, 30 frames at a time. I suspect this is
occuring due to background tasks or something like that interupting the
app. In the future I may go to a hard RT linux, but for now, I just
have time to try to reduce the number and frequency of frame drops.

I read on some linux websites that one can disable interrupts to
increase performance and/or reduce latencies.

My questions are

1. Is this an acceptable practice? If not, what are my other options?

2. How can I do this?

Would I use:
void local_irq_save(unsigned long flags);
void local_irq_restore(unsigned long flags);


3. What interupts should I consider disabling?

Ed


2009-01-21 05:34:24

by Robert Hancock

[permalink] [raw]
Subject: Re: disabling interupts

linux wrote:
> Please advise if this question is OT. (If so, where can I post it or
> read more about said topic?)
>
> I have an application that grabs frames from a frame grabber. It is
> dropping frames, sometimes, 30 frames at a time. I suspect this is
> occuring due to background tasks or something like that interupting the
> app. In the future I may go to a hard RT linux, but for now, I just
> have time to try to reduce the number and frequency of frame drops.
> I read on some linux websites that one can disable interrupts to
> increase performance and/or reduce latencies.
> My questions are
>
> 1. Is this an acceptable practice? If not, what are my other options?
>
> 2. How can I do this?
> Would I use:
> void local_irq_save(unsigned long flags);
> void local_irq_restore(unsigned long flags);
>
>
> 3. What interupts should I consider disabling?
>
> Ed

You haven't provided nearly enough details in order to answer this
question. What kind of frame grabber, what driver is it using? Where do
you think the frames are being dropped?