Apakah ada cara untuk mengetahui ukuran cache L1, L2, L3 dan RAM di Linux?
Apakah ada cara untuk mengetahui ukuran cache L1, L2, L3 dan RAM di Linux?
Jawaban:
Jika Anda telah lshwmenginstal:
$ sudo lshw -C memory
$ 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)
lshw(berlari dengan izin root tentu saja) tidak memberi saya informasi cache. tapi lscpudan dmidecodealat memberi saya hasilnya.
Jika Anda hanya peduli tentang ukuran, coba lscpudari util-linux.
$ 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
Seharusnya ada juga paket / perintah yang disebut x86info. Dengan asumsi Anda memiliki i386 / x86_64, x86info -charus memberikan informasi lebih rinci tentang cache.
$ x86info -c
x86info v1.30. Dave Jones 2001-2011
Feedback to <davej@redhat.com>.
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
$ 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
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 <linux-kernel@vger.kernel.org>
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, ...
index0dan index1keduanya level 1pada kernel v4.15, ini membingungkan. Pengkodean pencegahan 0-indeks? :-)
typeData (L1 cache data) dan index1 adalah tentang L1 dengan typeInstruksi (cache instruksi L1). Kemudian index2 adalah type Unified dan level2 (L2 cache, dapat menyimpan data dan instruksi)
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