Branko Badrljica <bran...@avtomatika.com> posted 4a01a58c.2040...@avtomatika.com, excerpted below, on Wed, 06 May 2009 16:58:20 +0200:
> Duncan wrote: >> Then, look at memory model. Here, with current kernels, I have only >> one option, Sparse. However [some have the] Flat and Discontiguous >> options as well. > I thought those extra options were just for NUMA systems and were about > how the memory from several NUMA nodes "fits together" ie whether it has > to form one continuos memory range or not. It's possible. The documentation on them is a bit limited, and I may have inferred more than was justified from the fact that the options there were so similar to the ones in my BIOS that (seemed to) control the >4-gig memory layout. It's also worth noting that I DO have a NUMA system here, so my somewhat trial and error method of finding what worked for me included that factor as well, and I may have misattributed the effects. Never-the-less, it was the two BIOS options and the two kernel options, that together I tweaked, until I came up with a config that gave me use of all of memory, the GART based IOMMU (without which I found I couldn't boot at all with >4 gig addressable memory, because my SIL_SATA PCI-X hardware and/or the kernel driver for it are evidently legacy-PCI and the kernel would halt trying to access the disk in DMA mode addressing above 4G RAM), and NUMA. Oh, something else I found didn't work, but this is a chipset specific errata I believe. AGP fast-writes simply don't work on this system. I had to disable them both in the BIOS and in xorg.conf. That's something else people might want to watch for. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman
