Enabling 64-bit on Gutsy

Post #306,486 by malraux 3/31/09 2:27:33 PM 3/31/09 2:30:44 PM Reply	Enabling 64-bit on Gutsy NFC how to do this. I have linux-image-2.6.22-14-386, linux-image-2.6.22-14-generic, and linux-image-2.6.22-14-server installed. The last two have descriptions that mention x86/x86_64, but no information as to which is being used. I have 6G in the box, but only 2.7 are being used. dmesg: [ 0.000000] Linux version 2.6.22-14-generic (buildd@terranova) (gcc version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)) #1 SMP Tue Feb 12 07:42:25 UTC 2008 (Ubuntu 2.6.22-14.52-generic) [ 0.000000] BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: 0000000000000000 - 000000000009ec00 (usable) [ 0.000000] BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved) [ 0.000000] BIOS-e820: 0000000000100000 - 00000000afe0ac00 (usable) [ 0.000000] BIOS-e820: 00000000afe0ac00 - 00000000afe0cc00 (ACPI NVS) [ 0.000000] BIOS-e820: 00000000afe0ec00 - 00000000afe5cc00 (reserved) [ 0.000000] BIOS-e820: 00000000afe5cc00 - 00000000afe5ec00 (ACPI data) [ 0.000000] BIOS-e820: 00000000afe5ec00 - 00000000b0000000 (reserved) [ 0.000000] BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved) [ 0.000000] BIOS-e820: 00000000fe000000 - 00000000ff000000 (reserved) [ 0.000000] BIOS-e820: 00000000ffb00000 - 0000000100000000 (reserved) [ 0.000000] BIOS-e820: 0000000100000000 - 00000001d0000000 (usable) [ 0.000000] Warning only 4GB will be used. [ 0.000000] Use a PAE enabled kernel. [ 0.000000] 3200MB HIGHMEM available. [ 0.000000] 896MB LOWMEM available. Regards, -scott Welcome to Rivendell, Mr. Anderson. Edited by malraux March 31, 2009, 02:30:44 PM EDT Expand All History
Post #306,496 by Another Scott 3/31/09 3:30:42 PM Reply	It seems to be a black hole... Looking through this thread, I see discussions of nVidia kernel modules conflicting with 64-bit kernels, enabling BigMem on 32-bit kernels, etc., etc. http://ubuntuforums....rnel+guide&page=6 Do you need 64-bitness, or do you just want to be able to use all your RAM? The 64-bit kernel should obviously do both, but maybe a tweak to the 32-bit kernel will do what you want. As to how one does go to 64-bits, my reading is you have to use a 64-bit installer to get the 64-bit kernel - http://ubuntuforums....it+kernel+upgrade As to how one installs a "bigmem" kernel, well it looks like you'll have to roll your own as Ubuntu doesn't provide one, unless things have changed: http://ubuntuforums....php/t-725567.html :-( Good luck. HTH. Cheers, Scott.
Post #306,497 by malraux 3/31/09 3:33:09 PM Reply	I just need the RAM But in order for Java to use > 4G, it needs to run as 64-bit. 4G might be enough, so I might try a bigmem kernel first. Regards, -scott Welcome to Rivendell, Mr. Anderson.
Post #306,512 by folkert 3/31/09 8:43:32 PM Reply	Re: I just need the RAM JAVA... and mysql. Those are the only two places 64-bit makes sense right now. Perhaps PostGres as well. But I'm out of that venue for the long term right now. Everything else "64 bit" is pretty much useless.
Post #306,509 by folkert 3/31/09 8:39:34 PM Reply	You have to use the "SERVER" kernel. The Server kernel uses large memory pages to get up to 64GB usable. In today's OS an d machine setup... you will never see it. There is also nVidia Kernel Modules you'll need to load. The Generic Kernel CAN ONLY use about 3.5GB of memory if you are lucky. Dump i386 and the generic kernel First boot selecting the server kernel. Hit ESC before it boots and select it. I've not seen any real benefits with 64bit except when I have 32GB or more memory and all of the programs running on the machine are compiled for only 64-bit... other wise you'll have to have both 64-bit and 32-bit extensions/libraries on the machine and you;ve effectively eliminated any real benefit. For about another year or so, I'll be sticking with 32-bit and large pages enabled. After than, I'll try it again.
Post #306,511 by malraux 3/31/09 8:43:30 PM Reply	Yeah, that didn't work. Individual processes can still have only 3G. Regards, -scott Welcome to Rivendell, Mr. Anderson.
Post #306,513 by folkert 3/31/09 8:45:09 PM Reply	Yeah well I just saw the "JAVA" thing... You have to install the 64-bit libraries and many other pieces to flip to the 64-bit kernel. It might be eaiser to just install with 64-bit versions. Yeah, I know. You and OSes and hardware... bad combo.

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