Messages in this thread | | | Date | Mon, 14 Mar 2005 11:36:43 +1100 | From | Peter Chubb <> | Subject | Re: User mode drivers: part 1, interrupt handling (patch for 2.6.11) |
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>>>>> "Jon" == Jon Smirl <jonsmirl@gmail.com> writes:
Jon> On Fri, 11 Mar 2005 14:36:10 +1100, Peter Chubb Jon> <peterc@gelato.unsw.edu.au> wrote: >> As many of you will be aware, we've been working on infrastructure >> for user-mode PCI and other drivers. The first step is to be able >> to handle interrupts from user space. Subsequent patches add >> infrastructure for setting up DMA for PCI devices.
Jon> I've tried implementing this before and could not get around the Jon> interrupt problem. Most interrupts on the x86 architecture are Jon> shared. Disabling the IRQ at the PIC blocks all of the shared
Fortunately, most interrupts on IA64, ARM, etc., are unshared. And with PCI-Express, the problem will go away. Even on X86, things aren't all bad: one can usually find a PCI slot which doesn't share interrupts with anything you care about.
The scenario I'm thinking about with these patches are things like low-latency user-level networking between nodes in a cluster, where for good performance even with a kernel driver you don't want to share your interrupt line with anything else.
-- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au The technical we do immediately, the political takes *forever* - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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