Ingo Molnar <[EMAIL PROTECTED]> wrote: > i cannot find Thomas' recent 2.6 one (Thomas, do you have a link to > it?), but i did one 5 years ago: > > http://people.redhat.com/mingo/irq-rewrite-patches/irq-cleanup-2.4.15-B1.bz2 > > in general it's a large but otherwise pretty dumb patch.
I wrote my own patch to test this last Friday. I found that removing all the regs pointer passing from the interrupt code reduced interrupt entry with a warm cache by 1 cpu cycle out of 87, and interrupt exit by 19 cycles out of 99. I can't tell from that exactly how many instructions/memory accesses have been removed since the FRV permits two instructions to be executed in one cycle under some circumstances, and two registers to be stored/loaded in one instruction. But the main gain in the exit path has to be due to recovery of the clobbered regs parameter due to a call inside a loop, possibly in handle_IRQ_event(). I'd expect i386 to do better in cycle reduction because it has fewer registers and so getting one back should gain more. David - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
