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

Stas Grabois sagig at radware.com
Mon Jun 27 11:02:29 UTC 2011


Try this:

http://www.open-mpi.org/software/hwloc/v1.0/

On 27/06/2011 13:25, clibup clibup wrote:
> 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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