disabling interupts

[linux <linux@celticblues.com>]

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