I think the hangs were actually CAUSED by the messages being printked. If I make those go away, it stops getting unhappy. (I suspect repeatedly printk-ing stuff from the middle of the scsi layer with interrupts disabled and other fun stuff occuring is not a good thing. Delays something or other long enough to trigger a watchdog timer and make the system go bye-bye.) Increasing the handle array thingy to 511 seems to have made the problem go away for me almost entirely. (Still periodic slight bus stalls from overrunning the scsi command queue (the test right before the "should never happen" test), but it recovers pretty quickly.) Throughput's a little over 160 million bytes per second on both writes and reads. That's about 20 million per second below the maximums (due to the stalls), but that's survivable at the moment... Close enough I can go home and get some sleep, anyway. Unresolved issues: That handle thingy should probably dynamically scale somehow. (Maybe the "out of handles" behavior could resize the array to the next 2^x-1 bump? I can try to whip up a patch to this effect if nobody thinks this is too crazy.) Bus stalls take to long to recover from, slowing throughput. (Pure scsi-ness, I may investigate later but haven't a CLUE on this right now. I'm guessing.) Rob __________________________________________________ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/