Each core shares the 4MB cache with its sibling core. There are a total of 4 cores 2 cores in 2 separate socketed physical cpus. Of the 5 examples this should be the most capable system processor-wise. Model name : Intel(R) Xeon(TM) CPU 3.60GHzĮxample 5. The number of siblings is twice the number of cores, which is another clue that this is a system with hyperthreading enabled. This example shows that processer 0 and 2 share the same physical cpu and 1 and 3 share the same physical cpu. Dual Single core CPU, Hyperthreading ENABLED Model name : Intel(R) Pentium(R) D CPU 3.00GHzĮxample 4. Model name : Intel(R) Xeon(R) CPU E5410 2.33GHzĪgain, each processor has its own core so this is a dual core system. That makes sense though, when considering 4 cores share that l2 cache. The number of siblings matches the number of cores so there are no Hyperthreading siblings.
Notice how each processor has its own core id. Model name : Intel(R) Pentium(R) 4 CPU 2.80GHz The physical cpu id is the same for both: 0. Notice how we have 2 siblings, but only 1 core. bin/cat /proc/cpuinfo | /bin/egrep ‘processor|model name|cache size|core|sibling|physical’Įxample 1: Single processor, 1 core, no HyperthreadingĮxample 2: Single processor, 1 core, Hyperthreading is enabled. If the number of cores = the number of siblings for a given physical processor, then hyperthreading is OFF. We must look at the siblings, cpu cores and core id to tell the difference. A logical cpu can be a hyperthreading sibling, a shared core in a dual or quad core, or a separate physical cpu. The kernel data Linux exposes in /proc/cpuinfo will show each logical cpu with a unique processor number.
The examples below details how we determine what kind of cpu(s) are present. Hyperthreading can provide a marginal (10%) for some server workloads like mysql, but dual core technology has essentially replaced hyperthreading in newer systems.Ī dual core cpu running at 3.0Ghz should be faster then a dual cpu (separate core) system running at 3.0Ghz due to the ability to share the cache at higher bus speeds.
In general Hyperthreading is considered older technology and is no longer supported in newer cpus. This may sound like an advantage, and in some situations it can be but in many cases new research and testing shows that the shared cache can be faster when the cpus are sharing the same or very similar tasks.
A dual processor (separate physical cpus) system differs in that each cpu will have its own level 2 cache. On the other hand, if you’re running two programs which compete for the same function units, there is no advantage at all to having both running “concurrently.” When one is running, the other is necessarily waiting on the same function units.Ī dual core processor literally has two times as many function units as a single-core processor, and can really run two programs concurrently, with no competition for function units.Ī dual core processor is built so that both cores share the same level 2 cache. It just has two execution contexts, so it can maybe achieve better function unit utilization by letting more than one program execute concurrently. Understanding /proc/cpuinfoĪ hyperthreaded processor has the same number of function units as an older, non-hyperthreaded processor. Ajeet Raina Follow Docker Captain, ARM Innovator & Docker Bangalore Community Leader.
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