"Natalie Protasevich" <[EMAIL PROTECTED]> writes: > On Nov 27, 2007 10:21 PM, Len Brown <[EMAIL PROTECTED]> wrote: >> commit c434b7a6aedfe428ad17cd61b21b125a7b7a29ce >> (x86: avoid wasting IRQs for PCI devices) >> created a concept of "IRQ compression" on i386 >> to conserve IRQ numbers on systems with many >> sparsely populated IO APICs. >> >> The same scheme was also added to x86_64, >> but later removed when x86_64 recieved an IRQ over-haul >> that made it unnecessary -- including per-CPU >> IRQ vectors that greatly increased the IRQ capacity >> on the machine. >> >> i386 has not received the analogous over-haul, >> and thus a previous attempt to delete IRQ compression >> from i386 was rejected on the theory that there may >> exist machines that actually need it. The fact is >> that the author of IRQ compression patch was unable >> to confirm the actual existence of such a system. > > Those systems did exist (and still exist actually). They used over 200 > irqs sometimes and with "normal" IRQ allocation they were failing even > before reaching half of their I/O configuration. So simple removal > wouldn't work for those, dynamic allocation sure would. They "scrolled > off the topic" though because new generations of such machines are not > 32 bit anymore. So the author didn't actually object :) it was the > other users of large 32 bit platforms that did.
Natalie. Did they just have over 200 irqs/gsis or did they actually use over 200 irqs? In particular is a large NR_IRQS plus dynamic vector allocation sufficient for all cases you know about? Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/