[Beowulf] Optimal BIOS settings for Tyan K8SRE

[stephen mulcahy]

Hi,

I'm maintaining a 20-node cluster of Tyan K8SREs (4GB RAM, dual Opteron
270s) which are being used primarily for Oceanographic modelling (MPICH2
running on Debian/Linux 2.6 kernel).

I had to make some tweaks to make all 4GB of RAM visible to the OS.

I'm now at the point where I'm considering a pass at performance tuning
the system. Before I start on OS level tuning, I'm trying to figure out
whether there are any performance improvements to be had from tweaking
BIOS settings, particularly those relating to Memory and ECC. I have a
reasonable conceptual understanding of what the various settings are doing
(and have glanced at the AMD BIOS developers guide for reference) but I am
very unclear on what the potential performance impact of any of these
settings are. Does anyone have any general advice or pointers to good
reference information on this?

My current settings are,

Hammer Configuration
	HT-LDT Frequency	Auto
	Dual-Core Enable	Enabled
	ECC Features
		ECC	Enabled
		ECC Scrub Redirection	Enabled
		Dram ECC Scrub CTL	Disabled
		Chip-Kill	Disabled
		DCACHE ECC Scrub CTL	Disabled
		L2 ECC Scrub CTL	Disabled

	Memory Hole
		4GB Memory Hole Adjust	Manual
		4GB Memory Hole Size	768 MB
		IOMMU	Enabled
		Size	32 MB
		Memhole mapping	Hardware

	Memory Config
		Swizzle Memory Banks	Enabled
		DDR clock jitter	Disabled
		DDR Data Transfer Rate	Auto
		Enable all memory clocks	Populated
		Controller config mode	Auto
		Timing config mode	Auto
	AMD PowerNow!	Disabled
	Node Memory Interleave	Auto
	Dram Bank Interleave	Auto
	GART Error Reporting	Disabled
	MTRR Mapping	Discrete


Any comments on those welcome.

Thanks,

-stephen


-- 
   Stephen Mulcahy    Applepie Solutions Ltd   http://www.aplpi.com
  Unit 30, Industry Support Centre, GMIT, Dublin Rd, Galway, Ireland.