Re: [gentoo-user] amd64 & 4G memory
On 18:43 Sat 11 Aug , Aleksey V. Kunitskiy wrote: > On Friday 10 August 2007 22:34, Volker Armin Hemmann wrote: > > So your 'lost' memory is not really lost > Why? If I have 3G of memory it is OK and 4G is a problem. Of course a few > MB(~100 actualy) of memory is not critical for me in this case, but I'd like > to understand why 4G is problem where logical address space is 64 bit and > physical is about ~40 bit. I think it's been explained pretty well in the 'ask Dan' link. I've read through that and the article is really one of the best layman's tech articles I've seen on the net so far. See, the problem is that the PCI-addresses are all located at the upper end of the 4Gig ram boundary. And _even if_ your system's already 64bit the problem remains because of compatibility issues - hardware vendors did not push the limit up (yet?) in order to be able to support programs, drivers, OSs and other hardware that relys on PCI being somewhere at the end of the 4Gigs... Some Mainboard vendors actually map the stuff out with BIOS hacks in order to make more memory available. This has happend on your machine because you only lack some lousy 100 MB (Jesus, I remember my ultra-fast p100 (It was a cyrix though) that was *so* proud of having 64 Megs...) which are used for PCI communications. If you had an older mainboard you would probably lack those ~100 MB + the amount of RAM your graphics card has, so, be happy ;-) Regards, Aleks pgpalRtHWoFH6.pgp Description: PGP signature
Re: [gentoo-user] amd64 & 4G memory
On Samstag, 11. August 2007, Aleksey V. Kunitskiy wrote: > On Friday 10 August 2007 22:34, Volker Armin Hemmann wrote: > > So your 'lost' memory is not really lost > > Why? If I have 3G of memory it is OK and 4G is a problem. Of course a few > MB(~100 actualy) of memory is not critical for me in this case, but I'd > like to understand why 4G is problem where logical address space is 64 bit > and physical is about ~40 bit. Bios. -- [EMAIL PROTECTED] mailing list
Re: [gentoo-user] amd64 & 4G memory
Aleksey V. Kunitskiy wrote: On Friday 10 August 2007 22:34, Volker Armin Hemmann wrote: So your 'lost' memory is not really lost Why? If I have 3G of memory it is OK and 4G is a problem. Of course a few MB(~100 actualy) of memory is not critical for me in this case, but I'd like to understand why 4G is problem where logical address space is 64 bit and physical is about ~40 bit. Let em start with a disclaimer: I don't have an amd64 system, so I'm not sure about the specifics of the system (didn't know that the kernel has no HIGHMEM requirement, for example). However, dmesg should still list the memory mappings in the first 40 lines or so, so that you can see where the memory is going. It should still be an E820 memory map, after all. -- [EMAIL PROTECTED] mailing list
Re: [gentoo-user] amd64 & 4G memory
On Friday 10 August 2007 22:34, Volker Armin Hemmann wrote: > So your 'lost' memory is not really lost Why? If I have 3G of memory it is OK and 4G is a problem. Of course a few MB(~100 actualy) of memory is not critical for me in this case, but I'd like to understand why 4G is problem where logical address space is 64 bit and physical is about ~40 bit. -- best regards, Aleksey V. Kunitskiy my public GPG/PGP key: http://www.alexey-kv.org.ua/pubkey.asc pgpzaNcewSX14.pgp Description: PGP signature
Re: [gentoo-user] amd64 & 4G memory
On Friday 10 August 2007 21:13, Tim wrote: > Hi. How are you checking the memory? /proc/meminfo :) > Can you post the first 30 lines or > so of dmesg or the output of 'cat /proc/meminfo'? Also, is your kernel > configured with HIGHMEM support? If so, what type? > > You may also consider checking in the BIOS for any memory options - some > video cards share system memory. I have 64 bit kernel and there is no need in HIGHMEM at all MemTotal: 4043012 kB MemFree: 3695820 kB Buffers: 14028 kB Cached: 144332 kB SwapCached: 0 kB Active: 199168 kB Inactive:84012 kB SwapTotal: 0 kB SwapFree:0 kB Dirty: 820 kB Writeback: 0 kB AnonPages: 124832 kB Mapped: 60024 kB Slab:28016 kB SReclaimable:14040 kB SUnreclaim: 13976 kB PageTables: 8528 kB NFS_Unstable:0 kB Bounce: 0 kB CommitLimit: 2021504 kB Committed_AS: 305060 kB VmallocTotal: 34359738367 kB VmallocUsed:311952 kB VmallocChunk: 34359425531 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 Hugepagesize: 2048 kB -- best regards, Aleksey V. Kunitskiy my public GPG/PGP key: http://www.alexey-kv.org.ua/pubkey.asc pgpGFNTzgd3P3.pgp Description: PGP signature
Re: [gentoo-user] amd64 & 4G memory
On Freitag, 10. August 2007, Aleksey V. Kunitskiy wrote: > Hi, > > I'm a bit confused, because before this moment I thought that 4G for amd64 > platform is normal memory size... > I've Asus a8n-e motherboard and AMD X2 cpu. Yesterday I've installed +1G > memory to my already installed 3G. Before this my system showed that all > 3072M of memory are avalible. After +1G instalation it shows 3948M of > avalible memory. > My questions are: where is the rest of the memory? Is 4G of memory a > problem for amd64 cpu? What is going on there o_O ? somewhere stuff like pci-space or kernel space has to be mapped. And that is at the end of the 4gb space. So your 'lost' memory is not really lost -- [EMAIL PROTECTED] mailing list
Re: [gentoo-user] amd64 & 4G memory
On 8/10/07, Aleksey V. Kunitskiy <[EMAIL PROTECTED]> wrote: > Hi, > > I'm a bit confused, because before this moment I thought that 4G for amd64 > platform is normal memory size... > I've Asus a8n-e motherboard and AMD X2 cpu. Yesterday I've installed +1G > memory to my already installed 3G. Before this my system showed that all > 3072M of memory are avalible. After +1G instalation it shows 3948M of > avalible memory. > My questions are: where is the rest of the memory? Is 4G of memory a problem > for amd64 cpu? What is going on there o_O ? Are you running a 64 bit kernel or a 32 bit kernel? If you are running a 32 bit kernel, you will have issues with large amounts of memory. However, if you are running a 64 bit kernel, you shouldn't have any issues. If you are running a 64 bit kernel, then you won't even have a High Memory Support option under the Processor Type and Features menu in make menuconfig. HTH- James -- [EMAIL PROTECTED] mailing list
Re: [gentoo-user] amd64 & 4G memory
Aleksey V. Kunitskiy wrote: Hi, I'm a bit confused, because before this moment I thought that 4G for amd64 platform is normal memory size... I've Asus a8n-e motherboard and AMD X2 cpu. Yesterday I've installed +1G memory to my already installed 3G. Before this my system showed that all 3072M of memory are avalible. After +1G instalation it shows 3948M of avalible memory. My questions are: where is the rest of the memory? Is 4G of memory a problem for amd64 cpu? What is going on there o_O ? Hi. How are you checking the memory? Can you post the first 30 lines or so of dmesg or the output of 'cat /proc/meminfo'? Also, is your kernel configured with HIGHMEM support? If so, what type? You may also consider checking in the BIOS for any memory options - some video cards share system memory. -- [EMAIL PROTECTED] mailing list
Re: [gentoo-user] amd64 & 4G memory
Aleksey V. Kunitskiy wrote: Before this my system showed that all 3072M of memory are avalible. After +1G instalation it shows 3948M of avalible memory. You're a lucky man! I have 3 GB in my PC (mobo Asus A8N-sli deluxe, amd64/x2-4800+) and bios shows 3 or ~2.8 GB depending on the graphic card used (with gf7900/256 bios reports only 2.8GB RAM, with gf6600/128 bios shows 3GB). And that is before any system even starts booting! I asked asus support about it. They answered it has something to do with the way address space for hardware components is remapped. Maybe here you can find better explanation: http://www.dansdata.com/askdan00015.htm Jarry -- ___ This mailbox accepts e-mails only from selected mailing-lists! Everything else is considered to be spam and therefore deleted. -- [EMAIL PROTECTED] mailing list