Date: Mon, 9 Dec 1996 16:33:49 +1100 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, proff@suburbia.net Cc: hackers@freebsd.org Subject: Re: strange problems with recent current Message-ID: <199612090533.QAA17144@godzilla.zeta.org.au>
next in thread | raw e-mail | index | archive | help
>P100/Triton mother board. 4 Triton/mb IDE drives, two scsi (ISA >adaptec), average 120 procs, 72Mb swap used (striped over the 4 >ide drives). This configuration hasn't changed, and I don't use the >console keyboard, infact..the console keyboard has been unplugged >(could this have any effect?) Not using the keyboard can only help. All those IDE drives are bad for the non-fast-interrupt (PCI) cy driver, at least if multi-mode is enabled. It takes 0.5 ms to transfer a typical 8K multi-block at 16MB/sec. Any more than that will cause silo overflows. Active drives on both controllers can certainly cause more than that, and very fast drives may be able to hog the cpu for any number of transfers. >> One per day is too many. > >cy15 is often going at 57.6k in both directions, the others are more >sporadic typical dial-up-user traffic (at 38.4). I moved cy15 onto sio1 >(on board 16550A uart) I would expect it to work up to 16 * 57.6k going in both directions. In raw mode, this takes about 70% overhead on a 486/33, about 40% of which is bus i/o overhead, 20% interrupt overhead, and 40% software overhead. Cooked mode has a much larger software overhead (5-10 times). A P100 should be enough faster to run some lines in cooked mode and actually do something besides serial i/o. However, if the PCI bus interface is 50% slower like David mentioned, then the bus i/o alone will take 60% of a P100 instead of only 40% :-]. >Dec 9 14:58:16 suburbia /kernel: sio1: 1 more silo overflow (total 17190) >Dec 9 14:58:21 suburbia /kernel: cy0: 2 more silo overflows (total 220) Not good. >This is actually quite a bit better than the cyclades (could just be the >12 vs 15 byte byffer) but still worse than the cyclades before the >"slow down". sio actually only uses 2 or 3 bytes of buffering above the interrupt threshold (the threshold is 14), while cy uses 6 bytes (the threshold is 6). The source must be edited to change the thresholds. >Load average is typically around 0.16 Load average doesn't show interrupt load. Use systat to see interrupt load for non-fast-interrupt handlers. Nothing shows the load for fast-interrupt handlers properly. Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199612090533.QAA17144>