On 32-bit x86, we have CONFIG_IRQBALANCE available, but not on 64-bit x86. Why not?
I ask, because this feature seems almost essential to obtaining reasonable latencies during heavy I/O with fast devices. My 32-bit Core2Duo MythTV box drops audio frames without it, but works perfectly *with* IRQBALANCE. My QuadCore box works very well in 32-bit mode with IRQBALANCE, but responsiveness sucks bigtime when run in 64-bit mode (no IRQBALANCE) during periods of multiple heavy I/O streams (USB flash drives). That's with both the 32 and 64 bit versions of Kubuntu Gutsy, so the software uses pretty much identical versions either way. As near as I can tell, when IRQBALANCE is not configured, all I/O device interrupts go to CPU#0. I don't think our CPU scheduler takes that into account when assigning tasks to CPUs, so anything sent to CPU0 runs with very high latencies. Or something like that. Why no IRQ_BALANCE in 64-bit mode ? - 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/