[CentOS] How many L1/L2 my cpu have ?

Mon Jun 27 10:25:57 UTC 2011
clibup clibup <clibup at gmail.com>

Hi

Could anybody explain me how to check how many L1/L2 cache my cpu have.
I'm using CentOS 5.6

*cat /proc/cpuinfo |grep CPU *

model name : Intel(R) Core(TM)2 Duo CPU T9300 @ 2.50GHz

model name : Intel(R) Core(TM)2 Duo CPU T9300 @ 2.50GHz

Diagram of a generic dual-core processor, with CPU-local level 1 caches, and
a shared, on-die level 2 cache.

*http://upload.wikimedia.org/wikipedia/commons/e/ec/Dual_Core_Generic.svg*

#########################
>From /proc/cpuinfo we see that CPU have 6MB L2 cache, but we see it doubled
and it's not true because according Intel specification we know that this
CPU have shared L2 cache.

*grep 'cache size' /proc/cpuinfo *

cache size : 6144 KB

cache size : 6144 KB

###################################

Here we can see that cpu have 6MiB L2 cache and 64KiB L1 cache

*dmesg |grep 'CPU: L' *

CPU: L1 I cache: 32K, L1 D cache: 32K

CPU: L2 cache: 6144K


L2 - true

L1 - not true because each CPU core have 64 KiB memory cache (Instruction
and Data)

############################################

Into sys directory we can find some information about cache size but again
not all information are true

L2 - not true

L1 - true

*cat /sys/devices/system/cpu/cpu*/cache/index*/size *

32K

32K

6144K

32K

32K

6144K

#####################################

getconf show information only for one core.

*getconf -a |grep CACHE *

LEVEL1_ICACHE_SIZE 32768

LEVEL1_DCACHE_SIZE 32768

LEVEL2_CACHE_SIZE 6291456


L1 - 64KiB - not true

L2 - 6MiB - true

############################

According the most powerful tool - x86info we can presume that we have:

 *x86info -c *


 Found 2 identical CPUs

Extended Family: 0 Extended Model: 1 Family: 6 Model: 23 Stepping: 6

Type: 0 (Original OEM)

CPU Model (x86info's best guess): Core 2 Duo P8600

Processor name string (BIOS programmed): Intel(R) Core(TM)2 Duo CPU T9300 @
2.50GHz

 Cache info

L1 Instruction cache: 32KB, 8-way associative. 64 byte line size.

L1 Data cache: 32KB, 8-way associative. 64 byte line size.

L2 cache: 6MB, 24-way set associative, 64-byte line size.

TLB info

Instruction TLB: 4x 4MB page entries, or 8x 2MB pages entries, 4-way
associative

Instruction TLB: 4K pages, 4-way associative, 128 entries.

Data TLB: 4MB pages, 4-way associative, 32 entries

L1 Data TLB: 4KB pages, 4-way set associative, 16 entries

L1 Data TLB: 4MB pages, 4-way set associative, 16 entries

Data TLB: 4K pages, 4-way associative, 256 entries.

64 byte prefetching.

Total processor threads: 2

This system has 1 dual-core processor running at an estimated 2.50GHz


L1 - 128Kib - true

L2 - 12 MiB - not true
##########################
Output form dmidecode is useless.

dmidecode -t processor
 L1 Cache Handle: 0x0005
 L2 Cache Handle: 0x0006
 L3 Cache Handle: Not Provided

##################################
Is there any tool which can clearly indicate how many L1/L2 cache cpu have.

If someone have any idea how to clearly designate L1/L2 cache don't hesitate
share your knowledge .. ;)
P.S.
Sorry for my English ...


Regards
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