Dual processor, AMD 64 machine freezing.

Haapanen, Tom tomh at waterloo.equitrac.com
Sun Feb 1 16:21:21 PST 2004

 Whoops ... looks like I got my aac and asr mixed up!  Sorry about that ...

As for the memory allocation ... is that something that FreeBSD *could* do
in the future?  Would that fit in with the kernel architecture?

And if that's not the case today, is there any advantage to balancing the
memory between the two CPUs?


-----Original Message-----
From: Andreas Braukmann [mailto:braukmann at tse-online.de] 
Sent: Sunday 01 February 2004 18:52
To: Haapanen, Tom
Cc: amd64 at freebsd.org
Subject: RE: Dual processor, AMD 64 machine freezing.

On 02/01/04 18:34:10 -0500 Haapanen, Tom wrote:

> I run a K8S Pro with dual 244s (couldn't find any 246s and the 248s 
> were just too dear for me) and 2 GB ... and I started off with an 
> Adaptec 2100S RAID, but had consistent panics when booting.  
> Apparently the aac driver isn't exactly 64-bit clean.

The 2100S isn't driven by aac(4) but by asr(4). The asr-driver is in fact
not 64-bit clean (as Scott Long stated multiple times :-/).
The aac-driver is perfectly fine with the 64 bits (for me). It survives
heavy i/o load without a hitch. I ran quite a bunch of tests (parallel
bonnie++ spreaded over multiple raid volumes and multiple file systems,
postmark, etc.) with my 2200S, 2120S and 5400S.

> P.S. For best performance, I think you really want to run 4x 512 MB.
> Running with two DIMMs means either you only get 64-bit memory access 
> (not
> 128-bit) or else you need to put both DIMMs into the CPU1 memory slots 
> (which means CPU2 will have to access those through hypertransport).

Thats theory. ;-)
Since the allocators don't know about the numa-like architecture memory
would be accessed through hyptertransport (statistically) more or less "half
of the time". (CPU0 ---> HT ---> MEM1 ;
CPU1 ---> HT ---> MEM0)


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