Date: Mon, 29 Jan 1996 22:54:05 +0100 From: se@zpr.uni-koeln.de (Stefan Esser) To: Craig Johnston <caj@tower.stc.housing.washington.edu> Cc: questions@freebsd.org Subject: Re: various questions Message-ID: <199601292154.AA03805@Sysiphos> In-Reply-To: Craig Johnston <caj@tower.stc.housing.washington.edu> "various questions" (Jan 29, 7:56)
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On Jan 29, 7:56, Craig Johnston wrote: } Subject: various questions } } Hello. I have a number of questions regarding FreeBSD: } } I run FreeBSD on a system with an Asus SP3G mboard, with an amd dx4-100 } cpu, and the latest flash bios version. I have 256k cache, and also do } have the tag SRAM installed. (this is what it is called? tag-dirty-some- } thing-or-other.. the extra piece of SRAM that is supposed to make } write-back work ok.) I use the onboard NCR chip and a PCI NIC. (a Boca } thingie with the AMD chip that seems to give me too many overruns. The } general consensus is that early versions of this card are massively broken, } no?) Can't comment on the Boca ... Is this a Lance based card ? That should work just fine ... } Anyway -- which PCI optimisations in the chipset settings for this } motherboard may I safely enable? I currently have all of them except } 'PCI posted write' enabled -- PCI to DRAM caching, PCI burst write, etc. } I had a random reboot with absolutely no messages at some point after } turning on the posted write, which may or may not be related, but I } turned it off to be safe. Is it ok, and beneficial to turn these on? } I was also told ISA GAT should be off, this is correct? Since I got the same motherboard (just without Dirty Tag RAM), and once read the Saturn technical data book, I guess I should respond ... :) The Saturn II in the SP3G can be savely used with all PCI options enabled. I.e. the PCI posted write option should not cause any trouble ... ISA GAT can cause problems with ISA DMA (e.g. if there is a sound card in the system). It should be disabled! } Wish I had more info on the random reboot, but I could find not even } a single burp in /var/log/messages, and nothing popped up on the screen } before it happened. I was making Octave at the time. (which takes a damn } long time!) If someone thinks it would be useful, I'll give full info } on my kernel config and system, but it doesn't really look likely there } will be enough info without even a diagnostic message to go on. Well, it may have been a random DRAM error. I do not like the fact, that the SP3G doesn't support parity, though the Saturn chip set does, and it would have been a no extra cost option. } Are there any tweaks for this mboard under FreeBSD? Should I fiddle with PCI } latencies, etc? I don't know what half the chipset options mean, and } who ever thought of actually documenting a motherboard. :( The PCI latency timer is only useful to prevent several PCI bus masters from locking out each other. There is some maximum time, that an I/O card can buffer data received (e.g. 50 micro seconds for some Ethernet cards) and if the card would not be granted access to the PCI bus within this time, a input buffer overrun would occur and the packets contents was lost ... Since the latency is measured in bus clocks and even the short time of 50us is equivalent to some 1500 PCI bus cycles, there should not be much of a problem. With a (typical) latency timer setting of 80, there could be nearly 20 PCI chips competing for the bus. (To be sure, I'd consider 10 devices the maximum with that latency timer value, though.) It only really matters if you got something like 3 4channel Ethernet cards and an Adpatec 3940 in your system :) } Second question -- are FreeBSD 2.1 binaries in the distribution compiled } with -m486 and other optimisations? Or should I go back and do this? } I'm mostly concerned about the shells, window managers and the Xserver. I generally do such a recompilation. } Another question: is it likely there is much I can strip from my kernel } besides disabling various things in my kernel config file that will make } it smaller? I've got 32 megs in this box but I am concerned with the amt } of memory FreeBSD seems to eat, and would like to eliminate every } unecessary byte everywhere I can.. perhaps a pointer to info on stripping } down FreeBSD? I've already gotten rid of all unecessary daemons etc. and } stripped my config file to the bone. (didn't remove npx0 tho.. ;) ) Most device driver don't consume that much memory, but NFS does! There is now an option that disables only the NFS server functions, but allows a system to act as a NFS client. Too bad that the AMD automounter requires that server functionality ... BTW: (If you happen to have that much time to spend :) I'd really love to have bytebench results for the SP3G with both WRITE-BACK and WRITE-THROUGH secondary cache. The Dirty Tag RAM seems to cost some $20, and it might be a good way to improve my systems effective memory throughput. Regards, STefan -- Stefan Esser, Zentrum fuer Paralleles Rechnen Tel: +49 221 4706021 Universitaet zu Koeln, Weyertal 80, 50931 Koeln FAX: +49 221 4705160 ============================================================================== http://www.zpr.uni-koeln.de/~se <se@ZPR.Uni-Koeln.DE>
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