Missing MTRR ?

From: J.A. MagallÃn
Date: Wed Sep 30 2009 - 07:23:21 EST


Hi all...

I'm using 2.6.31.1 on a box like this:
- Intel(R) Core(TM)2 CPU 6420 @ 2.13GHz (dual core)
- 4Gb RAM

I find that MTRR setup is this:
lorelei:/proc# cat mtrr
reg00: base=0x0cff00000 ( 3327MB), size= 1MB, count=1: uncachable
reg01: base=0x0d0000000 ( 3328MB), size= 256MB, count=1: uncachable
reg02: base=0x0e0000000 ( 3584MB), size= 512MB, count=1: uncachable
reg03: base=0x0cfea6000 ( 3326MB), size= 4KB, count=1: write-back

I have no mtrr for my main memory, is this a problem for speed ?

dmesg:

BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000008f000 (usable)
BIOS-e820: 000000000008f000 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 00000000cee2a000 (usable)
BIOS-e820: 00000000cee2a000 - 00000000ceeb1000 (ACPI NVS)
BIOS-e820: 00000000ceeb1000 - 00000000cfe00000 (usable)
BIOS-e820: 00000000cfe00000 - 00000000cfe0d000 (reserved)
BIOS-e820: 00000000cfe0d000 - 00000000cfe94000 (usable)
BIOS-e820: 00000000cfe94000 - 00000000cfee9000 (ACPI NVS)
BIOS-e820: 00000000cfee9000 - 00000000cfeec000 (usable)
BIOS-e820: 00000000cfeec000 - 00000000cfef1000 (ACPI data)
BIOS-e820: 00000000cfef1000 - 00000000cfef2000 (usable)
BIOS-e820: 00000000cfef2000 - 00000000cfeff000 (ACPI data)
BIOS-e820: 00000000cfeff000 - 00000000cff00000 (usable)
BIOS-e820: 00000000cff00000 - 00000000d0000000 (reserved)
BIOS-e820: 00000000f0000000 - 00000000f8000000 (reserved)
BIOS-e820: 00000000fff00000 - 0000000100000000 (reserved)
BIOS-e820: 0000000100000000 - 000000012c000000 (usable)
DMI 2.4 present.
last_pfn = 0x12c000 max_arch_pfn = 0x400000000
MTRR default type: write-back
MTRR fixed ranges enabled:
00000-9FFFF write-back
A0000-FFFFF uncachable
MTRR variable ranges enabled:
0 base 0CFF00000 mask FFFF00000 uncachable
1 base 0D0000000 mask FF0000000 uncachable
2 base 0E0000000 mask FE0000000 uncachable
3 base 0CFEA6000 mask FFFFFF000 write-back
4 disabled
5 disabled
6 disabled
7 disabled
x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
last_pfn = 0xcff00 max_arch_pfn = 0x400000000
initial memory mapped : 0 - 20000000
init_memory_mapping: 0000000000000000-00000000cff00000
0000000000 - 00cfe00000 page 2M
00cfe00000 - 00cff00000 page 4k
kernel direct mapping tables up to cff00000 @ 8000-e000
init_memory_mapping: 0000000100000000-000000012c000000
0100000000 - 012c000000 page 2M
kernel direct mapping tables up to 12c000000 @ c000-12000
...
No NUMA configuration found
Faking a node at 0000000000000000-000000012c000000
Bootmem setup node 0 0000000000000000-000000012c000000
NODE_DATA [0000000000001000 - 0000000000005fff]
bootmap [000000000000d000 - 00000000000327ff] pages 26
(8 early reservations) ==> bootmem [0000000000 - 012c000000]
#0 [0000000000 - 0000001000] BIOS data page ==> [0000000000 - 0000001000]
#1 [0000006000 - 0000008000] TRAMPOLINE ==> [0000006000 - 0000008000]
#2 [0001000000 - 0001873430] TEXT DATA BSS ==> [0001000000 - 0001873430]
#3 [0037c64000 - 0037fef32c] RAMDISK ==> [0037c64000 - 0037fef32c]
#4 [000009e000 - 0000100000] BIOS reserved ==> [000009e000 - 0000100000]
#5 [0001874000 - 000187415e] BRK ==> [0001874000 - 000187415e]
#6 [0000008000 - 000000c000] PGTABLE ==> [0000008000 - 000000c000]
#7 [000000c000 - 000000d000] PGTABLE ==> [000000c000 - 000000d000]
found SMP MP-table at [ffff8800000fe200] fe200
[ffffea0000000000-ffffea00043fffff] PMD -> [ffff880028600000-ffff88002bffffff] on node 0
Zone PFN ranges:
DMA 0x00000000 -> 0x00001000
DMA32 0x00001000 -> 0x00100000
Normal 0x00100000 -> 0x0012c000
Movable zone start PFN for each node
early_node_map[8] active PFN ranges
0: 0x00000000 -> 0x0000008f
0: 0x00000100 -> 0x000cee2a
0: 0x000ceeb1 -> 0x000cfe00
0: 0x000cfe0d -> 0x000cfe94
0: 0x000cfee9 -> 0x000cfeec
0: 0x000cfef1 -> 0x000cfef2
0: 0x000cfeff -> 0x000cff00
0: 0x00100000 -> 0x0012c000
On node 0 totalpages: 1031572
DMA zone: 56 pages used for memmap
DMA zone: 106 pages reserved
DMA zone: 3821 pages, LIFO batch:0
DMA32 zone: 14280 pages used for memmap
DMA32 zone: 833085 pages, LIFO batch:31
Normal zone: 2464 pages used for memmap
Normal zone: 177760 pages, LIFO batch:31

TIA

--
J.A. Magallon <jamagallon()ono!com> \ Software is like sex:
\ It's better when it's free
Mandriva Linux release 2010.0 (Cooker) for x86_64
Linux 2.6.29.3-desktop-1mnb (gcc 4.3.2 (GCC) #1 Wed May
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