Date: Tue, 6 Jul 1999 11:49:18 -0400 From: Richard Cownie <tich@ma.ikos.com> To: Andrew MacIntyre <andymac@bullseye.apana.org.au>, Dmitry Flitmann <dflit@nns.ru> Cc: freebsd-smp@FreeBSD.ORG Subject: Re: Intel SC450NX hangs under high disk/memory load (2) Message-ID: <99070612032100.30449@par28.ma.ikos.com> References: <Pine.OS2.3.95.990706085442.237A-100000@CENTRAL>
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On Mon, 05 Jul 1999, Andrew MacIntyre wrote:
> On Mon, 5 Jul 1999, Dmitry Flitmann wrote:
>
> > Any ideas - are there any problems with memory over 512M -
> > either kernel, or maybe some drivers/controllers?
>
> {...}
>
> > >MAXUSERS is 512 (or 256)
>
> I haven't seen any responses to your query via the list, so...
>
> Given that I remember your described usage patterns, I seem to recall
> seeing recommendations to use a smaller MAXUSERS value (say 128) and
> directly modify the specific values which may need to be increased, such
> as NMBCLUSTERS (hope I got that right...). I think it had to do with the
> MAXUSERS calculation causing kernel memory usage to expand too much.
I'm running 4.0-CURRENT from about 6 June on an SC450NX with
4 x Xeon-500 and 4GB DRAM. The kernel is built with these sizing
options:
maxusers 256
options VM_KMEM_SIZE_MAX=0x20000000UL
options NMBCLUSTERS=8192
If you don't set VM_KMEM_SIZE_MAX, I believe the default is 80MB,
which is not much for a machine with >1GB of DRAM. However, this
would probably cause a panic rather than the behaviour you're
seeing.
I believe Linux is good for approx 1GB of DRAM, and latest kernels
can be tuned to support 2GB DRAM. As far as I know FreeBSD 3.x
supports 2GB DRAM (not sure about 3GB ?) - you need a recent 4.0-CURRENT
to support the full 4GB. It turns out to be 4GB - 97MB, because
the SC450NX chipset/bios put some of the DRAM above the 4GB address
boundary.
Richard Cownie (tich@ma.ikos.com)
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