dell 4gb ram PAE - asi dlhsie/delsi

[Milan Kerslager]

On Mon, Apr 07, 2003 at 02:41:11PM +0200, patrik rybar wrote:
> mam maly problem s ktorym sa krutim stale dokola medzi supportom Dell-u a Redhat-u
> 
> o co ide :
> 
> dell 6600 4gb ram redhat as 2.1 , vidim v systeme iba 3,6 gb ram
> 
> je to sposobene tym, ze :
> 
> Systems that support hot-plug, hot-swap, and hot-add PCI capabilities,
> with 4GB of memory installed may not report or have access to all
> physical memory. An indication of this is the operating system
> reporting less available memory than the amount of memory physically
> present in the system.
> 
> Hot-plug, hot-swap and hot-add PCI capabilities require that a certain
> amount of memory in the upper range of the 4GB address space be
> reserved. PCI devices installed in a system require all of their
> resources to be defined and mapped in the 32-bit address (4GB) space.
> The Flash Memory and APIC controllers are located at the top of memory
> at address 0xFEC00000 and above, other PCI devices are defined below
> this address range. Physical memory, which exists in this high address
> space, may be unusable by the operating system.
> 
> ve woknech sa to riesi parametrom /PAE do boot.ini

"enterprise" kernel se od ostatnich v RH lisi tim, ze ma zapnute PAE
(tj. zpristupneni pameti nad hranici 4GB na x86 architekture a to pouze
u jader optimalizovanych pro i686 nebo Athlon). Pouziti PAE znamena
penalizaci vykonu cca 6% a take bylo kdesi linux-kernel uvedeno, ze u
gigabitovych karet snizuje vykon az 3x (myslim, ze to bude z technickych
principu porad stejne). Pokud tedy nemusite, enterprise kernel
NEpouzivejte.

Krome toho, ze nektere chipsety neumi presunout rezervovanou pamet nad
hranici 4GB a proste pamet "sezerou", musite tedy uvazit, zda ozelite
400MB pameti nebo se smirite s penalizaci vykonu.

Ciste teoreticky by melo byt lepsi jit do 64bitove architektury, kdyz uz
posilhavate po takovem vykonu.

> support redhat tvrdi, ze to musi automaticky slapat pri pouziti
> entreprise kernel-u

To maji pravdu. Pokud to tak neni, bude neco spatne v domluve jadra a
pouziteho chipsetu.

> The enterprise kernel is able to use up to 64GB pagecache without any
> modifications.  "If more than 4 Gigabytes is used then answer "64GB"
> here. This selection turns Intel PAE (Physical Address Extension) mode
> on.  PAE implements 3-level paging on IA32 processors. PAE is fully
> supported by Linux, PAE mode is implemented on all recent Intel
> processors (Pentium Pro and better). NOTE: If you say "64GB" here,
> then the kernel will not boot on CPUs that don't support PAE! "
> 
> 
> dell ma odkazuje na vyrobcu OS
> 
> vyrobca OS robi mrtveho chrobaka a dava rady typu "mate kabel v elektrike ?"
> 
> ani po update na najnovsi kernel pre RH AS ziadna zmena
> uname -a
> Linux dbsm 2.4.9-e.16enterprise #1 SMP Mon Mar 17 16:37:14 EST
> ree
>           total     used        free     shared    buffers       cached
> Mem:       3605424     186700     3418724     28      7332        77364
> -/+ buffers/cache:     102004     3503420
> Swap:       6192996        0     6192996
> 
> riesil niekto tento problem ?

-- 
                        Milan Kerslager
                        E-mail: milan.kerslager na pslib.cz
                        WWW:    http://www.pslib.cz/~kerslage/