Hallo, Am Mon, 01 May 2006, Andre Tann schrieb:
David Haller, Samstag, 29. April 2006 17:22:
Aufpassen muss man halt, dass die Hardware auch korrekt mit soviel Speicher umgehen kann. Auf 32bit x86 bremst PAE u.U. doch ziemlich, so dass mit >= 4 GB das gesamte RAM langsamer ist als mit (ca.) <= 3.5 GB.
Was ist denn PAE?
Physical Address Extension. Siehe http://de.wikipedia.org/wiki/PAE
Im übrigen dachte ich, daß der normale Kernel gar nicht mit mehr als 4 GB umgehen kann.
Doch, klar, nur kompiliert SUSE die default Kernel nicht entsprechend. ==== /usr/src/linux/Documentation/Configure.help (Kernel 2.4.25) ==== High Memory support CONFIG_NOHIGHMEM Linux can use up to 64 Gigabytes of physical memory on x86 systems. However, the address space of 32-bit x86 processors is only 4 Gigabytes large. That means that, if you have a large amount of physical memory, not all of it can be "permanently mapped" by the kernel. The physical memory that's not permanently mapped is called "high memory". If you are compiling a kernel which will never run on a machine with more than 960 megabytes of total physical RAM, answer "off" here (default choice and suitable for most users). This will result in a "3GB/1GB" split: 3GB are mapped so that each process sees a 3GB virtual memory space and the remaining part of the 4GB virtual memory space is used by the kernel to permanently map as much physical memory as possible. If the machine has between 1 and 4 Gigabytes physical RAM, then answer "4GB" here. 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! The actual amount of total physical memory will either be auto detected or can be forced by using a kernel command line option such as "mem=256M". (Try "man bootparam" or see the documentation of your boot loader (grub, lilo or loadlin) about how to pass options to the kernel at boot time.) If unsure, say "off". 4GB CONFIG_HIGHMEM4G Select this if you have a 32-bit processor and between 1 and 4 gigabytes of physical RAM. 64GB CONFIG_HIGHMEM64G Select this if you have a 32-bit processor and more than 4 gigabytes of physical RAM. ==== Und /proc/cpuinfo bei mir: vendor_id : AuthenticAMD cpu family : 6 model : 1 model name : AMD-K7(tm) Processor stepping : 2 cpu MHz : 499.040 cache size : 512 KB [..] flags : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat mmx syscall mmxext 3dnowext 3dnow bogomips : 996.14 Wie du siehst taucht selbst auf diesem inzwischen alten Prozessor von 1999 (der erste und langsamste AMD Athlon) das 'pae' flag auf. Und das MoBo kann eh nur 768 MB. HTH, -dnh -- So Linus, what are we doing tonight? The same thing we do every night Tux. Try to take over the world!