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Difference between Processors and CPU core

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http://serverfault.com – can any one please clarify the difference between actual no of processors and CPU cores. in my case i am having Intel Xeon® Processor E5620 as per intels product page: its having # of Cores 4 # of Threads 8 and cat /proc/cpuinfo |grep processor|wc -l is showing 16 so what is this 16 showing here?. I am planning to virtualize this machine with xen to 4 vms,each with 4 cpu.So it will be better if i can understand about these values and assigning vcpus to guest vm. (HowTos)

taskli's picture
Submitted by taskli on 10/03/2012

Stories similar to Difference between Processors and CPU core

2x Xeon E5620 . 16 Cores altogether. /proc/cpuinfo shows cache is only @ 4096kb

According to intel this should have 12MB of "smart cache". Doing searched for E5620 and CPUinfo shows the correct number:

cache size : 12288 KB

However mine shows this:

processor : 15 v endor_id : GenuineIntel cpu family : 6 model : 44 model name : Intel(R) Xeon(R) CPU

2x Xeon E5620 . 16 Cores altogether. /proc/cpuinfo shows cache is only @ 4096kb

According to intel this should have 12MB of "smart cache". Doing searched for E5620 and CPUinfo shows the correct number:

cache size : 12288 KB

However mine shows this:

processor : 15 v endor_id : GenuineIntel cpu family : 6 model : 44 model name : Intel(R) Xeon(R) CPU

AMD currently announce that the already shipped 8 and 12 cores processor Magny-Cours for OEM and selected manufacturers. Magny-Cours is a server CPU next generation from AMD. This new processor contains 2 cores of Istanbul. Because AMD does not have the original octal-core, the Magny-Cours 8 cores is built based on 2 Istanbul processors.

Wrong Processor Info 36 weeks 2 hours ago

I'm using Intel i5-2430M processor which is a dual core processor, but the output of /proc/cpuinfo shows four cores. Why? Is is because of hyper-threading?

If yes, is there any way I can see the actual number of cores?

Also, how can I see the sizes of L1 and L2 caches?

Output of /proc/cpuinfo: http://pastebin.ubuntu.com/1206427/

For some reason /proc/cpuinfo is only displaying one core from a 16 core processor. However hwinfo --cpu shows the 16 cores. I have ACPI enable in the bios and I have cleared the noacpi tags out of the grub.cfg file.

Hi,

Could you please Tell me the command to find the number of cores in red hat box?

I have tried cat cat /proc/cpuinfo | grep processor | wc -l command to find the number of processers.

But need to fond the number of cores.

Is there any difference between core and processor?

Please help on this.

Regards, Vikas.

My box is using intel i7 with hyperthreading enabled. So it has 8 logical processors. I am confused about their numbering.

I checked the /proc/cpuinfo file, the processor id, core id, and siblings do not AT ALL give any information about the REAL topology of the processors (e.g., the processor ids range from 0 to 7, and all the core ids are 0).

Can anybody explain this to me?

I was looking around on Wikipedia, and ran across the UltraSPARC T2 processor. This is a processor with 8 cores (8 physical processors) and 8 threads per core (64 logical processors!)

I'm aware of Intel's Hyper-Threading and other technologies, and I know collisions between the threads have the possibility of decreasing the processor's throughput.

I have two servers at hand, both with 16 cores. The first is running Debian, the second running Ubuntu.

I have written a small multithreaded java app that creates 16 threads.