Messages in this thread | | | Subject | Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-6 | From | Lee Revell <> | Date | Thu, 09 Dec 2004 15:16:13 -0500 |
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On Thu, 2004-12-09 at 20:04 +0100, Esben Nielsen wrote: > IRQ threading makes the system more predictable but for many, many > devices it is very expensive. I am predicting that many interrupt routines > have to be turned back to running in interrupt context.
It's important to keep in mind that for the type of applications that would want PREEMPT_DESKTOP, the IRQ threading is only necessary because of the amount of work the IDE subsystem does in hardirq context. There was some discussion a while back and Jens posted a patch to move the IDE IO completion to a softirq. IIRC there was not a lot of comment on it. But, it seems to me that this approach would give the most favorable balance of performance and low latency for many uses. My tests show that with softirq preemption this should allow jackd to run at 64 frames or so without IRQ threading.
Lee
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