Apakah ada cara untuk mengetahui ukuran L1, L2, L3 cache dan RAM di Linux?

Apakah ada cara untuk mengetahui ukuran cache L1, L2, L3 dan RAM di Linux?

Jika Anda telah lshwmenginstal:

$ sudo lshw -C memory

Contoh

$ sudo lshw -C memory
...
  *-cache:0
       description: L1 cache
       physical id: a
       slot: Internal L1 Cache
       size: 32KiB
       capacity: 32KiB
       capabilities: asynchronous internal write-through data
  *-cache:1
       description: L2 cache
       physical id: b
       slot: Internal L2 Cache
       size: 256KiB
       capacity: 256KiB
       capabilities: burst internal write-through unified
  *-cache:2
       description: L3 cache
       physical id: c
       slot: Internal L3 Cache
       size: 3MiB
       capacity: 8MiB
       capabilities: burst internal write-back
  *-memory
       description: System Memory
       physical id: 2a
       slot: System board or motherboard
       size: 8GiB
     *-bank:0
          description: SODIMM DDR3 Synchronous 1334 MHz (0.7 ns)
          product: M471B5273CH0-CH9
          vendor: Samsung
          physical id: 0
          serial: 67010644
          slot: DIMM 1
          size: 4GiB
          width: 64 bits
          clock: 1334MHz (0.7ns)
     *-bank:1
          description: SODIMM DDR3 Synchronous 1334 MHz (0.7 ns)
          product: 16JTF51264HZ-1G4H1
          vendor: Micron Technology
          physical id: 1
          serial: 3749C127
          slot: DIMM 2
          size: 4GiB
          width: 64 bits
          clock: 1334MHz (0.7ns)

lscpu

Jika Anda hanya peduli tentang ukuran, coba lscpudari util-linux.

Contoh

$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    2
Core(s) per socket:    2
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 37
Model name:            Intel(R) Core(TM) i5 CPU       M 560  @ 2.67GHz
Stepping:              5
CPU MHz:               1199.000
BogoMIPS:              5319.88
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              3072K
NUMA node0 CPU(s):     0-3

x86info

Seharusnya ada juga paket / perintah yang disebut x86info. Dengan asumsi Anda memiliki i386 / x86_64, x86info -charus memberikan informasi lebih rinci tentang cache.

Contoh

$ x86info -c
x86info v1.30.  Dave Jones 2001-2011
Feedback to <[email protected]>.

Found 4 identical CPUs
Extended Family: 0 Extended Model: 2 Family: 6 Model: 37 Stepping: 5
Type: 0 (Original OEM)
CPU Model (x86info's best guess): Core i7 (Nehalem) [Clarkdale/Arrandale]
Processor name string (BIOS programmed): Intel(R) Core(TM) i5 CPU       M 560  @ 2.67GHz

Cache info
 L1 Instruction cache: 32KB, 4-way associative. 64 byte line size.
 L1 Data cache: 32KB, 8-way associative. 64 byte line size.
 L2 (MLC): 256KB, 8-way associative. 64 byte line size.
TLB info
 Instruction TLB: 2MB or 4MB pages, fully associative, 7 entries
 Instruction TLB: 4K pages, 4-way associative, 64 entries.
 Data TLB: 4KB or 4MB pages, fully associative, 32 entries.
 Data TLB: 4KB pages, 4-way associative, 64 entries
 Data TLB: 4K pages, 4-way associative, 512 entries.
 Data TLB: 4KB or 4MB pages, fully associative, 32 entries.
 Data TLB: 4KB pages, 4-way associative, 64 entries
 64 byte prefetching.
 Data TLB: 4K pages, 4-way associative, 512 entries.
Found unknown cache descriptors: dd 
Total processor threads: 4
This system has 1 dual-core processor with hyper-threading (2 threads per core) running at an estimated 2.65GHz

Anda dapat mencoba perintah ini.

$sudo dmidecode -t cache

Contoh

$ sudo dmidecode -t cache | grep -iE "leve|installed"
    Configuration: Enabled, Socketed, Level 1
    Installed Size: 32 kB
    Installed SRAM Type: Asynchronous
    Configuration: Enabled, Socketed, Level 2
    Installed Size: 256 kB
    Installed SRAM Type: Burst
    Configuration: Enabled, Socketed, Level 3
    Installed Size: 3072 kB
    Installed SRAM Type: Burst

Untuk melihat RAM cukup tambahkan sakelar tambahan -t memory.

$ sudo dmidecode -t cache -t memory

Referensi

• menemukan ukuran cache L2 di Linux

getconf

getconf -a | grep CACHE

memberi:

LEVEL1_ICACHE_SIZE                 32768
LEVEL1_ICACHE_ASSOC                8
LEVEL1_ICACHE_LINESIZE             64
LEVEL1_DCACHE_SIZE                 32768
LEVEL1_DCACHE_ASSOC                8
LEVEL1_DCACHE_LINESIZE             64
LEVEL2_CACHE_SIZE                  262144
LEVEL2_CACHE_ASSOC                 8
LEVEL2_CACHE_LINESIZE              64
LEVEL3_CACHE_SIZE                  20971520
LEVEL3_CACHE_ASSOC                 20
LEVEL3_CACHE_LINESIZE              64
LEVEL4_CACHE_SIZE                  0
LEVEL4_CACHE_ASSOC                 0
LEVEL4_CACHE_LINESIZE              0

Atau untuk satu level:

getconf LEVEL2_CACHE_SIZE

Yang paling keren dari antarmuka ini adalah ia hanya membungkus sysconffungsi POSIX C (argumen cache adalah ekstensi non-POSIX), sehingga bisa digunakan dari kode C juga.

Diuji di Ubuntu 16.04.

Instruksi x86 CPUID

Instruksi CPUID x86 juga menawarkan informasi cache, dan dapat langsung diakses oleh userland: https://en.wikipedia.org/wiki/CPUID

glibc tampaknya menggunakan metode itu untuk x86. Saya belum mengonfirmasi langkah debugging / instruksi, tetapi sumber untuk 2.28 sysdeps/x86/cacheinfo.cmelakukan itu:

__cpuid (2, eax, ebx, ecx, edx);

TODO membuat contoh C minimal, malas sekarang, bertanya di: /programming/14283171/how-to-receive-l1-l2-l3-cache-size-using-cpuid-instruction-instruction-in-x86

ARM juga memiliki mekanisme yang ditentukan arsitektur untuk menemukan ukuran cache melalui register seperti Cache Size ID Register (CCSIDR), lihat Manual Programmer ARMv8 '11,6 "Penemuan cache" untuk tinjauan umum.

Ada file khusus yang diekspor ke / sys sysfssistem file Linux sejak 2008:

https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-devices-system-cpu

What:       /sys/devices/system/cpu/cpu*/cache/index*/<set_of_attributes_mentioned_below>
Date:       July 2014(documented, existed before August 2008)
Description:    Parameters for the CPU cache attributes

    allocation_policy:
        - WriteAllocate: allocate a memory location to a cache line
                 on a cache miss because of a write
        - ReadAllocate: allocate a memory location to a cache line
                on a cache miss because of a read
        - ReadWriteAllocate: both writeallocate and readallocate

    coherency_line_size: the minimum amount of data in bytes that gets
                 transferred from memory to cache

    level: the cache hierarchy in the multi-level cache configuration

    number_of_sets: total number of sets in the cache, a set is a
            collection of cache lines with the same cache index

    physical_line_partition: number of physical cache line per cache tag

    shared_cpu_list: the list of logical cpus sharing the cache

    shared_cpu_map: logical cpu mask containing the list of cpus sharing
            the cache

    size: the total cache size in kB

    type:
        - Instruction: cache that only holds instructions
        - Data: cache that only caches data
        - Unified: cache that holds both data and instructions

    ways_of_associativity: degree of freedom in placing a particular block
                of memory in the cache

    write_policy:
        - WriteThrough: data is written to both the cache line
                and to the block in the lower-level memory
        - WriteBack: data is written only to the cache line and
                 the modified cache line is written to main
                 memory only when it is replaced

File ID:

What:       /sys/devices/system/cpu/cpu*/cache/index*/id
Date:       September 2016
Contact:    Linux kernel mailing list <[email protected]>
Description:    Cache id

    The id provides a unique number for a specific instance of
    a cache of a particular type. E.g. there may be a level
    3 unified cache on each socket in a server and we may
    assign them ids 0, 1, 2, ...

    Note that id value can be non-contiguous. E.g. level 1
    caches typically exist per core, but there may not be a
    power of two cores on a socket, so these caches may be
    numbered 0, 1, 2, 3, 4, 5, 8, 9, 10, ...

cpuid

Pilihan lain adalah program cpuid . Ini menggunakan CPUIDinstruksi dan tidak memerlukan root. Ini juga dapat bekerja melalui cpuidmodul kernel Linux.

cache and TLB information (2):
   0x59: data TLB: 4K pages, 16 entries
   0xba: data TLB: 4K pages, 4-way, 64 entries
   0x4f: instruction TLB: 4K pages, 32 entries
   0xc0: data TLB: 4K & 4M pages, 4-way, 8 entries
   0x80: L2 cache: 512K, 8-way, 64 byte lines
   0x30: L1 cache: 32K, 8-way, 64 byte lines
   0x0e: L1 data cache: 24K, 6-way, 64 byte lines

Perhatikan bahwa pada CPU konsumen umum L1 dan L2 cache adalah per core, sedangkan L3 cache dibagi oleh semua core.

jika Anda hanya menginginkan L3 maka grep "cache size" < /proc/cpuinfoitu sudah cukup.

Namun karena cara L3 cache dibagi di antara cpu archs berbeda, nilainya mungkin perlu normalisasi