The easiest way to get informations about the CPU in Linux is by using the lscpu command, which is a part of util-linux package. The data is collected from sysfs and /proc/cpuinfo, let’s see how this work, also in this post we will use /proc/cpuinfo and dmidecode.
Source code: lscpu.c
lscpuArchitecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 8 On-line CPU(s) list: 0-7 Thread(s) per core: 2 Core(s) per socket: 4 Socket(s): 1 NUMA node(s): 1 Vendor ID: GenuineIntel CPU family: 6 Model: 60 Model name: Intel(R) Core(TM) i7-4771 CPU @ 3.50GHz Stepping: 3 CPU MHz: 902.984 CPU max MHz: 3900.0000 CPU min MHz: 800.0000 BogoMIPS: 6995.99 Virtualization: VT-x L1d cache: 32K L1i cache: 32K L2 cache: 256K L3 cache: 8192K NUMA node0 CPU(s): 0-7 Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm epb invpcid_single ssbd ibrs ibpb stibp kaiser tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid xsaveopt dtherm ida arat pln pts flush_l1d
Most of the information is self explanatory however some of the more important ones:
Socket(s): 1, Physical chip which is connected into the motherboard’s socket.
Core(s) per socket: 4, Number of physical cores a socket contains.
Thread(s) per core: 2, Number of threads a physical core contains.
CPU(s): 8, Logical cores, number of CPU’s that are used by the Operating System.
Display Level 1,Level 2, Level 3 cache information, online status and minimum and maximum frequency.
lscpu -e -aCPU NODE SOCKET CORE L1d:L1i:L2:L3 ONLINE MAXMHZ MINMHZ 0 0 0 0 0:0:0:0 yes 3900.0000 800.0000 1 0 0 1 1:1:1:0 yes 3900.0000 800.0000 2 0 0 2 2:2:2:0 yes 3900.0000 800.0000 3 0 0 3 3:3:3:0 yes 3900.0000 800.0000 4 0 0 0 0:0:0:0 yes 3900.0000 800.0000 5 0 0 1 1:1:1:0 yes 3900.0000 800.0000 6 0 0 2 2:2:2:0 yes 3900.0000 800.0000 7 0 0 3 3:3:3:0 yes 3900.0000 800.0000
Print out a parsable format
lscpu -p# The following is the parsable format, which can be fed to other # programs. Each different item in every column has an unique ID # starting from zero. # CPU,Core,Socket,Node,,L1d,L1i,L2,L3 0,0,0,0,,0,0,0,0 1,1,0,0,,1,1,1,0 2,2,0,0,,2,2,2,0 3,3,0,0,,3,3,3,0 4,0,0,0,,0,0,0,0 5,1,0,0,,1,1,1,0 6,2,0,0,,2,2,2,0 7,3,0,0,,3,3,3,0
Parsable format and select the columns
lscpu -p=CPU,ONLINE# The following is the parsable format, which can be fed to other # programs. Each different item in every column has an unique ID # starting from zero. # CPU,Online 0,Y 1,Y 2,Y 3,Y 4,Y 5,Y 6,Y 7,Y
Information about the physical chip
dmidecode -t processor# dmidecode 3.0 Getting SMBIOS data from sysfs. SMBIOS 2.7 present. Handle 0x0053, DMI type 4, 42 bytes Processor Information Socket Designation: SOCKET 1150 Type: Central Processor Family: Other Manufacturer: Intel ID: C3 06 03 00 FF FB EB BF Version: Intel(R) Core(TM) i7-4771 CPU @ 3.50GHz Voltage: 1.2 V External Clock: 100 MHz Max Speed: 3900 MHz Current Speed: 3504 MHz Status: Populated, Enabled Upgrade: Socket BGA1155 L1 Cache Handle: 0x004D L2 Cache Handle: 0x004E L3 Cache Handle: 0x004F Serial Number: Not Specified Asset Tag: Fill By OEM Part Number: Fill By OEM Core Count: 4 Core Enabled: 4 Thread Count: 8 Characteristics: 64-bit capable
Cache information
dmidecode -t cache# dmidecode 3.0 Getting SMBIOS data from sysfs. SMBIOS 2.7 present. Handle 0x004D, DMI type 7, 19 bytes Cache Information Socket Designation: CPU Internal L1 Configuration: Enabled, Not Socketed, Level 1 Operational Mode: Write Back Location: Internal Installed Size: 256 kB Maximum Size: 256 kB Supported SRAM Types: Unknown Installed SRAM Type: Unknown Speed: Unknown Error Correction Type: Single-bit ECC System Type: Other Associativity: 8-way Set-associative Handle 0x004E, DMI type 7, 19 bytes Cache Information Socket Designation: CPU Internal L2 Configuration: Enabled, Not Socketed, Level 2 Operational Mode: Write Back Location: Internal Installed Size: 1024 kB Maximum Size: 1024 kB Supported SRAM Types: Unknown Installed SRAM Type: Unknown Speed: Unknown Error Correction Type: Single-bit ECC System Type: Unified Associativity: 8-way Set-associative Handle 0x004F, DMI type 7, 19 bytes Cache Information Socket Designation: CPU Internal L3 Configuration: Enabled, Not Socketed, Level 3 Operational Mode: Write Back Location: Internal Installed Size: 8192 kB Maximum Size: 8192 kB Supported SRAM Types: Unknown Installed SRAM Type: Unknown Speed: Unknown Error Correction Type: Single-bit ECC System Type: Unified Associativity: 16-way Set-associative
Read cpuinfo from /proc
cat /proc/cpuinfoWatch current frequency for each CPU
watch -n 1 "cat /proc/cpuinfo | grep -i 'processor\|mhz'"