Linux/Dual Core vs Dual Proc

cores.sh
cores.sh:
 * 1) !/bin/sh
 * 2) Programmed by Kenneth Burgener 2010

LOGICAL=$( grep "processor" /proc/cpuinfo | wc -l ) PHYSICAL=$( grep "physical id" /proc/cpuinfo | sort | uniq | wc -l ) SIBLINGS=$( grep "siblings" /proc/cpuinfo | head -n 1 | awk '{ print $3 }' ) CORES=$( grep "cpu cores" /proc/cpuinfo | head -n 1 | awk '{ print $4 }' ) LM=$( grep "lm" /proc/cpuinfo >/dev/null ; echo $? ) PHYSICAL_ALT=$(( $PHYSICAL / $SIBLINGS )) MCORE=no HT=no X64=no

if [ $PHYSICAL -eq 0 ] ; then PHYSICAL=$LOGICAL SIBLINGS=1 CORES=1 fi if [ $SIBLINGS -eq $CORES -a $CORES -ge 2 ] ; then MCORE=yes HT=no fi if [ $SIBLINGS -ge 2 -a $CORES -eq 1 ] ; then MCORE=no HT=yes fi if [ $SIBLINGS -gt $CORES -a $CORES -gt 1 ] ; then MCORE=yes HT=yes fi if [ $LM -eq 0 ] ; then X64=yes fi

echo "Logical CPUs:    $LOGICAL" echo "Physical CPUs:   $PHYSICAL (or $PHYSICAL_ALT)" echo "Package Siblings: $SIBLINGS (HT+Cores)" echo "Package Cores:   $CORES" echo "Multi-core:      $MCORE" echo "Hyper-threading: $HT" echo "64bit capable:   $X64" echo echo "Summary:         $PHYSICAL proc + $CORES core + $HT ht = $LOGICAL threads"

cpuinfo_cores.sh: grep -e "\(model name\|processor\|physical id\|siblings\|core id\|cpu cores\)" /proc/cpuinfo

Dual Core vs Dual Proc
"As you can see, the move to dual-core is definitely a win for consumers. Since they are more affordable than dual processor systems, but offer the same or better performance, they are becoming the standard for modern computer systems." 

(Howto: Linux detect or find out a dual-core cpu)

"The 'ht' in 'flags' field of /proc/cpuinfo indicate that the processor supports the Machine Specific Registers to report back HT or multi-core capability. Additional fields (listed down below) in the CPU records of /proc/cpuinfo will give more precise information about the CPU topology as seen by the operating system."  /proc/cpuinfo "physical id"	Physical package id of the logical CPU "siblings"	Total number of logical processors(includes both threads and cores) in the physical package currently in use by the OS "cpu cores"	Total number of cores in the physical package currently in use by the OS "core id"	Core id of the logical CPU

"To identify if the physical package is purely multi-threaded or purely multi-core capable or both, then in addition to the "ht" flag, applications need to parse all the above mentioned fields. Following logic can be used to identify the CPU capabilities as seen by the OS."  /proc/cpuinfo "siblings == cpu cores >= 2" - Indicates that the physical package is multi-core capable and is not Hyper-threading capable "siblings >= 2" && "cpu cores == 1" - Indicates that the physical package is Hyper-threading capable and has one cpu core "siblings > cpu cores > 1" - Indicates that the physical package is both Hyper-threading and multi-core capable

"More recent Linux Kernels [LK] (like 2.6.17) have the CPU topology exported in sysfs as well. This mechanism is simpler and faster compared to the previously mentioned /proc interface. Below listed fields exported under /sys/devices/system/cpu/cpuX/topology/ provide the complete topology information."  /sys/devices/system/cpu/cpuX/topology/ physical_package_id	Physical package id of the logical CPU core_id		Core id of the logical CPU core_siblings		Siblings mask of all the logical CPUs in a physical package thread_siblings	Siblings mask of all the logical CPUs in a CPU core

Hamming Weight (number of bits set) of siblings mask will give the physical package capabilities. “HW(core_siblings) == HW(thread_siblings) >= 2” - Indicates that the physical package is Hyper-threading capable and has one cpu core “HW(core_siblings) >= 2” && “HW(thread_siblings) == 1” - Indicates that the physical package is multi-core capable and is not Hyper-threading capable “HW(core_siblings) > HW(thread_siblings) > 1” - indicates that the physical package is both Hyper-threading and multi-core capable

"Hyperthreading (HT) is only a feature of Intel CPUs. Current Intel x86 processors based on the Core microarchitecture (Core2Duo, Core2Quad, etc.) do not have hyperthreading, but there are some earlier Pentium 4-based Pentium and Xeon processors that are both dual-core and hyperthreaded. To determine whether a system is multi-processor, multi-core, hyperthreaded or a combination of the three, look at the "physical id", "siblings" and "cpu cores" values in /proc/cpuinfo while running a non-Xen kernel.* If "siblings" and "cpu cores" match, the system does not have hyperthreading or hyperthreading is turned off in the BIOS. If they differ, the system has hyperthreading. The "cpu cores" value also shows the number of cores per processor. The "physical id" value is different for each processor socket, so the number of unique "physical id" values equals the number of processor sockets in use on the system. It is worth noting that the presence of the "ht" flag in the "cpuflags" section of /proc/cpuinfo does not necessarily indicate that a system has hyperthreading capabilities. That flag indicates that the processor is capable of reporting the number of siblings it has, not that it has hyperthreading."

If you look at /proc/cpuinfo there are two fields of relevance: "siblings" and "cpu cores".  "siblings" = (ht per cpu package) * (# of cores per cpu package) "cpu cores" = (# of cores per cpu package) Thus: ht per cpu package = "siblings" / "cpu cores"

So when I see 4 entries in /proc/cpuinfo, all with "siblings : 2" and "cpu cores : 1", that means I have two single-core hyperthreading CPUs? - yes

/proc/cpuinfo source code is here: linux-mc/arch/i386/kernel/cpu/proc.c seq_printf(m, "physical id\t: %d\n", phys_proc_id[n]); seq_printf(m, "siblings\t: %d\n", 		c->x86_num_cores * smp_num_siblings); seq_printf(m, "core id\t\t: %d\n", cpu_core_id[n]); seq_printf(m, "cpu cores\t: %d\n", c->x86_num_cores);

Understanding /proc/cpuinfo
How many physical processors are there? grep 'physical id' /proc/cpuinfo | sort | uniq | wc -l

How many virtual processors are there? grep ^processor /proc/cpuinfo | wc -l

Are the processors dual-core (or multi-core)? grep 'cpu cores' /proc/cpuinfo cpu cores      : 2 cpu cores      : 2 cpu cores      : 2 cpu cores      : 2
 * "2" indicates the two physical processors are dual-core, resulting in 4 virtual processors.


 * If "1" was returned, the two physical processors are single-core. If the processors are single-core, and the number of virtual processors is greater than the number of physical processors, the CPUs are using hyper-threading. Hyper-threading is supported if ht is present in the CPU flags and you are using an SMP kernel.

Are the processors 64-bit? A 64-bit processor will have lm ("long mode") in the flags section of cpuinfo. A 32-bit processor will not. grep 'lm' /proc/cpuinfo

What do the CPU flags mean?
 * The CPU flags are briefly described in the kernel header file cpufeature.h.

Source: Understanding /proc/cpuinfo

AMD Athlong 64 X2 Dual Core Processor 5000+
Source: Our kids new Compaq computer system

model name     : AMD Athlon(tm) 64 X2 Dual Core Processor 4400+

processor      : 1 physical id    : 0 siblings       : 2 core id        : 0 cpu cores      : 2

processor      : 1 physical id    : 0 siblings       : 2 core id        : 1 cpu cores      : 2

flags: ht lm

Dual P4 with HT (maybe)
Source

NOTE: I think this is really a single proc with HT.

processor      : 0 physical id    : 0 siblings       : 2 core id        : 0 cpu cores      : 1

processor      : 1 physical id    : 0 siblings       : 2 core id        : 0 cpu cores      : 1

flags: ht

Dual Core AMD X2
Single proc, Dual Core, no HT

Source

model name     : AMD Athlon(tm) 64 X2 Dual Core Processor 4400+

processor      : 0 physical id    : 0 siblings       : 2 core id        : 0 cpu cores      : 2

processor      : 1 physical id    : 0 siblings       : 2 core id        : 1 cpu cores      : 2

flags: ht lm

Dual Proc Dual Core Xeons (maybe)
Source

NOTE: I think this is really a Dual Proc Single Core with HT

model name : Intel(R) Xeon(TM) MP CPU 3.66GHz cpu MHz : 3670.025

processor  : 0 physical id : 0 siblings   : 2 core id    : 0 cpu cores  : 1

processor  : 1 physical id : 0 siblings   : 2 core id    : 0 cpu cores  : 1

processor  : 2 physical id : 3 siblings   : 2 core id    : 3 cpu cores  : 1

processor  : 3 physical id : 3 siblings   : 2 core id    : 3 cpu cores  : 1

flags: ht lm

Intel Core2 Duo
Single proc, dual core, no HT

Source

Dell inspiron 1420 model name   : Intel(R) Core(TM)2 Duo CPU     T7250  @ 2.00GHz cpu MHz       : 800.000

processor   : 0 physical id : 0 siblings    : 2 core id     : 0 cpu cores   : 2

processor   : 1 physical id : 0 siblings    : 2 core id     : 1 cpu cores   : 2

flags: ht lm

Dual Proc Xeon with HT
Dual proc, single cores, with HT

Source

model name : Intel(R) Xeon(TM) CPU 2.40GHz cpu MHz : 2400.627

processor : 0 physical id : 0 siblings : 2

processor : 1 physical id : 0 siblings : 2

processor : 2 physical id : 3 siblings : 2

processor : 3 physical id : 3 siblings : 2

flags : ht

grep ^processor /proc/cpuinfo | wc -l
 * 1) Number of logical processors: 4

grep 'physical id' /proc/cpuinfo | sort | uniq | wc -l
 * 1) Number of physical processors: 2

grep 'cpu cores' /proc/cpuinfo
 * 1) Number of cores: 0

grep 'siblings' /proc/cpuinfo
 * 1) Is hyperthreading? yes (2 siblings > 0 cores)

Dual Proc Single Core Hyper threading Xeon
Dual proc, single cores, with HT

AppLabs - iov-admin1 - 1U Server

Verified 2 processors.

model name     : Intel(R) Xeon(TM) CPU 2.66GHz cpu MHz        : 2666.009

processor      : 0 physical id    : 0 siblings       : 2 core id        : 0 cpu cores      : 1

processor      : 1 physical id    : 0 siblings       : 2 core id        : 0 cpu cores      : 1

processor      : 2 physical id    : 3 siblings       : 2 core id        : 0 cpu cores      : 1

processor      : 3 physical id    : 3 siblings       : 2 core id        : 0 cpu cores      : 1

flags          : ht

grep ^processor /proc/cpuinfo | wc -l
 * 1) Number of logical processors: 4

grep 'physical id' /proc/cpuinfo | sort | uniq | wc -l
 * 1) Number of physical processors: 2

grep 'cpu cores' /proc/cpuinfo
 * 1) Number of cores: 1

grep 'siblings' /proc/cpuinfo
 * 1) Is hyperthreading? yes (2 sib > 1 cores)

Dual Proc Quad Core Xeon
Dual proc, quad core, no HT

AppLabs - Hitachi BS 1000 - Hypertown Blade (used in Trend Micro testing)

vendor_id      : GenuineIntel cpu family     : 6 model          : 15 model name     : Intel(R) Xeon(R) CPU           X5355  @ 2.66GHz stepping       : 7 cpu MHz        : 2666.806 cache size     : 4096 KB

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 syscall nx lm constant_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr lahf_lm flags          : ht bogomips        : 5332.34

processor      : 0 physical id    : 0 siblings       : 4 core id        : 0 cpu cores      : 4

processor      : 1 physical id    : 1 siblings       : 4 core id        : 0 cpu cores      : 4

processor      : 2 physical id    : 0 siblings       : 4 core id        : 1 cpu cores      : 4

processor      : 3 physical id    : 1 siblings       : 4 core id        : 1 cpu cores      : 4

processor      : 4 physical id    : 0 siblings       : 4 core id        : 2 cpu cores      : 4

processor      : 5 physical id    : 1 siblings       : 4 core id        : 2 cpu cores      : 4

processor      : 6 physical id    : 0 siblings       : 4 core id        : 3 cpu cores      : 4

processor      : 7 physical id    : 1 siblings       : 4 core id        : 3 cpu cores      : 4

grep ^processor /proc/cpuinfo | wc -l
 * 1) Number of logical processors: 8

grep 'physical id' /proc/cpuinfo | sort | uniq | wc -l
 * 1) Number of physical processors: 2

grep 'cpu cores' /proc/cpuinfo | uniq
 * 1) Number of cores: 4

grep 'siblings' /proc/cpuinfo | uniq
 * 1) Is hyperthreading? no (4 sib = 4 cores)

Dell PowerEdge R910 - Quad Proc Eight Core
Dell PowerEdge R910

Logical CPUs:    64 Physical CPUs:   4 Package Siblings: 16 (HT+Cores) Package Cores:   8 Multi-core:      yes Hyper-threading: yes 64bit capable:   yes

Summary:         4 proc + 8 core + yes ht = 64 threads

model name     : Intel(R) Xeon(R) CPU           X7560  @ 2.27GHz bogomips       : 4521.98

processor      : 0 vendor_id      : GenuineIntel cpu family     : 6 model          : 46 model name     : Intel(R) Xeon(R) CPU           X7560  @ 2.27GHz stepping       : 6 cpu MHz        : 2261.060 cache size     : 24576 KB physical id     : 0 siblings       : 16 core id        : 0 cpu cores      : 8 apicid         : 0 fpu            : yes fpu_exception  : yes cpuid level    : 11 wp             : yes 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 syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr sse4_1 sse4_2 popcnt lahf_lm bogomips       : 4522.12 clflush size   : 64 cache_alignment : 64 address sizes  : 44 bits physical, 48 bits virtual power management: [8]

processor      : 1 vendor_id      : GenuineIntel cpu family     : 6 model          : 46 model name     : Intel(R) Xeon(R) CPU           X7560  @ 2.27GHz stepping       : 6 cpu MHz        : 2261.060 cache size     : 24576 KB physical id     : 1 siblings       : 16 core id        : 0 cpu cores      : 8 apicid         : 32 fpu            : yes fpu_exception  : yes cpuid level    : 11 wp             : yes 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 syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr sse4_1 sse4_2 popcnt lahf_lm bogomips       : 4522.03 clflush size   : 64 cache_alignment : 64 address sizes  : 44 bits physical, 48 bits virtual power management: [8]

...

processor      : 47 vendor_id      : GenuineIntel cpu family     : 6 model          : 46 model name     : Intel(R) Xeon(R) CPU           X7560  @ 2.27GHz stepping       : 6 cpu MHz        : 2261.060 cache size     : 24576 KB physical id     : 3 siblings       : 16 core id        : 3 cpu cores      : 8 apicid         : 103 fpu            : yes fpu_exception  : yes cpuid level    : 11 wp             : yes 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 syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr sse4_1 sse4_2 popcnt lahf_lm bogomips       : 4522.06 clflush size   : 64 cache_alignment : 64 address sizes  : 44 bits physical, 48 bits virtual power management: [8]

...

processor      : 63 vendor_id      : GenuineIntel cpu family     : 6 model          : 46 model name     : Intel(R) Xeon(R) CPU           X7560  @ 2.27GHz stepping       : 6 cpu MHz        : 2261.060 cache size     : 24576 KB physical id     : 3 siblings       : 16 core id        : 11 cpu cores      : 8 apicid         : 119 fpu            : yes fpu_exception  : yes cpuid level    : 11 wp             : yes 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 syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr sse4_1 sse4_2 popcnt lahf_lm bogomips       : 4521.98 clflush size   : 64 cache_alignment : 64 address sizes  : 44 bits physical, 48 bits virtual power management: [8]

Hitachi BS2000
Intel Xeon E5540 Nehalem 2.53GHz 4 x 256KB L2 Cache 8MB L3 Cache LGA 1366 80W Quad-Core Server Processor

Intel® Xeon® Processor E5540 (8M Cache, 2.53 GHz, 5.86 GT/s Intel® QPI) System Information Manufacturer: HITACHI Product Name: BladeSymphony E55 Version: 0020G55100 Serial Number: 4600C80 T943000149 UUID: 53EED748-3000-AF87-DD11-31FF00000000 Wake-up Type: Power Switch SKU Number: None Family: None

Base Board Information Manufacturer: SUPERMICRO Product Name: X8DTE-HTC01a Version: 555G301041GD1M0 Serial Number: 93300030 Asset Tag: None Features: Board is a hosting board Board is replaceable Location In Chassis: None Chassis Handle: 0x0003 Type: Motherboard Contained Object Handles: 0

vendor_id      : GenuineIntel cpu family     : 6 model          : 26 model name     : Intel(R) Xeon(R) CPU           E5540  @ 2.53GHz stepping       : 5 cpu MHz        : 1596.000 cache size     : 8192 KB

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 syscall nx rdtscp lm constant_tsc ida pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm bogomips       : 5066.78

processor      : 0 physical id    : 0 siblings       : 8 core id        : 0 cpu cores      : 4

processor      : 1 physical id    : 0 siblings       : 8 core id        : 1 cpu cores      : 4

processor      : 2 physical id    : 0 siblings       : 8 core id        : 2 cpu cores      : 4

processor      : 3 physical id    : 0 siblings       : 8 core id        : 3 cpu cores      : 4

processor      : 4 physical id    : 1 siblings       : 8 core id        : 0 cpu cores      : 4

processor      : 5 physical id    : 1 siblings       : 8 core id        : 1 cpu cores      : 4

processor      : 6 physical id    : 1 siblings       : 8 core id        : 2 cpu cores      : 4

processor      : 7 physical id    : 1 siblings       : 8 core id        : 3 cpu cores      : 4

processor      : 8 physical id    : 0 siblings       : 8 core id        : 0 cpu cores      : 4

processor      : 9 physical id    : 0 siblings       : 8 core id        : 1 cpu cores      : 4

processor      : 10 physical id    : 0 siblings       : 8 core id        : 2 cpu cores      : 4

processor      : 11 physical id    : 0 siblings       : 8 core id        : 3 cpu cores      : 4

processor      : 12 physical id    : 1 siblings       : 8 core id        : 0 cpu cores      : 4

processor      : 13 physical id    : 1 siblings       : 8 core id        : 1 cpu cores      : 4

processor      : 14 physical id    : 1 siblings       : 8 core id        : 2 cpu cores      : 4

processor      : 15 physical id    : 1 siblings       : 8 core id        : 3 cpu cores      : 4

grep ^processor /proc/cpuinfo | wc -l
 * 1) Number of logical processors: 16

grep 'physical id' /proc/cpuinfo | sort | uniq | wc -l
 * 1) Number of physical processors: 2

grep 'cpu cores' /proc/cpuinfo | uniq
 * 1) Number of cores: 4

grep 'siblings' /proc/cpuinfo | uniq
 * 1) Is hyperthreading? yes (8 sib > 4 cores)