Date: Wed, 20 Mar 1996 22:36:45 -0800 From: Paul Traina <pst@shockwave.com> To: Bruce Evans <bde@zeta.org.au> Cc: hackers@FreeBSD.org Subject: Re: real time interrupts in FreeBSD? Message-ID: <199603210636.WAA13682@precipice.shockwave.com> In-Reply-To: Your message of "Thu, 21 Mar 1996 16:13:18 %2B1100." <199603210513.QAA22241@godzilla.zeta.org.au>
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Thanks much, your and Julian's message have got me going. I'm going to try to live with 1ms clocks and see how that works (maybe I can raise it once I get good statistics). I need this magic delay anywhere from 4 to 80 times a second (depending upon the size of the frame I'm downloading from the camera). Do you feel it's better to acquire timer 0 once, set my 1ms interrupt rate, and leave the ms timer running until the camera device is no longer open, or do you think that when I need to download a frame, I should switch the clock rate, do my wait, restore the clock rate, and go on? One would have me changing the timer rate up to 80 times a second, which will make keeping accurate time on the box particulary nasty, the other will put the box into 1ms timer resolution mode, potentially for LONG periods of time, and therfore waste a fair bit of CPU in interrupt processing. Both are bad situations. Oh for the want of another CTC hooked up to an interrupt line. :-(
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