Questions tagged [multi-core]

A multi-core CPU is a kind of CPU that has two or more actual chips inside it (known as cores). This allows a computer to actually be processing multiple things at once and is often seen as the solution to continuing Moore's law.

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Can one core perform several operations/instructions during one tick (because core has different execution units)?

A core has its own execution units and load/store buffers (additional "cache" - in addition to L1). Do those execution units have their own registers? Do cores also have their own dedicated registers?...
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Intel X vs Intel K CPU gaming [closed]

I'm looking to build a PC, and want eight RAM slots. For eight RAM slots, I need to choose motherboards with X-series chipsets, which requires an X-series CPU. Intel example of K-series CPU: Core i7-...
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Do multi-core processors have internal hardware for randomly changing in which core the instructions are executed?

A friend of mine says that a process always jumps between cores even if you pin a process to a specific core within operating system. He says that the processor manufacturers do this so that the ...
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Has CPU inter-core communication become slower?

I'd be pretty amazed if it had but maybe somebody can help me understand. I ran SiSoft Sandra Lite 2014's 'Processor Multi-Core Efficiency' test (which returns an 'Inter-Core Bandwidth' value) on my ...
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cuda matrix multiplication, gives incorrect result

I'm new to cuda programming. I tried to write a simple matrix multiplication code for practice purposes. Each thread calculates one element of the output matrix by traversing through the corresponding ...
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Why does Windows 10 have CPU core parking disabled?

Why does Windows 10 come with core parking disabled? It seems to me, that core parking is good in most cases. Especially considering Turbo Boost does not work until some cores are parked. Also why ...
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launching multiple instances and performances

I am making some benchmark tests and I use "truebench". This is a simple C program which just do a memset and a memcpy several times. On my laptop, when I launch only one instance I obtain 62s but ...
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How to utilize all cores on high-end CPUs using ffmpeg

I have a high-end HPE ProLiant DL325 G10 server with an AMD EPYC 7401P 24-core/48-thread CPU, 128GB DDR4 RAM, and a Intel P4800x PCIe NVMe. I tried to run ffmpeg to convert a video (MKV) to MP4 for ...
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How many threads can I run in my program?

I have a python program that uses the threading module and runs multithreads that executes a function. The number 8 below is the number of threads in the program but I need to know what is the number ...
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What does NUMA node distance signify?

I have a processor with 4 NUMA nodes. When I access the distance information on each of the nodes, I get the output as in the image here. From the first look, it appears that it signifies relative ...
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VirtualBox in VirtualBox CPU core usage

Background: I am attempting to run a VirtualBox VM within a VirtualBox VM. The first host machine is running atop an Intel 4670k, with Intel Virtualization Technology enabled, with 4 total cores ...
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Is there a significant issue to allocating all available cores to one VM if that is the only major task running?

I have a one-off task that requires me to use a VM to fix a build bug a software project using SCons (Python). The testing cycle is fairly short, resulting in frequent rebuilds. I'm using a 4-core ...
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Is it possible to merge CPU cores?

Back in the past there was something called hyperthreading where a single CPU core acted like two cores. But is it possible to merge two CPU cores to an single one to improve performance on programs ...
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Can Windows make use of 16+ core processors? [closed]

There's currently a number of processors on the market with 12, 14, 16, 16 32 cores (AMD Threadripper, Intel i9) and so on. Can Windows 10 even make use of this power? We know that it can support up ...
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Real cores or threads in an i5 7500T?

They say an i5 7500T has 4 cores (so, in this case 4 threads). When I, for instance, calculate the 1 millionth Fibonacci number (single thread only, every number is dependent on its predecessor) using ...
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Find core used from CPU utilization?

I have average and peak CPU utilization(in percentage) of a linux server with me . Mainly couple of web apps are deployed on the machine. I need to decide what AWS machine suits me based on that. AWS ...
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If i5 has no hyperthreading why it has more threads than cores

I have read at a lot of places that i5 does not have hyperthreading and that i7 is i5 + hyperthreading. If it is true, how come many i5 processors have more threads than cores(4 cores and 8 threads) ...
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On a multi-core Windows PC, why does a single process only occasionally use all cores?

For years, I had the impression that a single process can only use at most one core of the CPU, but recently I found two examples where a single process used all the cores of a multi-core Windows ...
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Force process and kernel module to one core exclusively [duplicate]

I'm just in the phase of evaluating new possibilities, so this question may be a bit strange. I have a Quad-Core CPU which has to do some realtime tasks (it has access to some GPIOs, so this is ...
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Can I have Windows OS dedicate one or 2 cores to a specific prog./application?

I can often times find benchmarks that compare performance on certain tasks such as for gaming ( Frames per second). However, I have long wanted to use my multiple cores to quickly switch between apps ...
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How multithreading works on multicore cpu in linux..? [closed]

In one interview I got one question, If I have dual core cpu,can I run one thread on both CPU at a time? If possible how it is works.?
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How many CPU cores can Firefox Quantum utilize?

I have a webapp that is very CPU intensive (multiple nested loops running over large dataset). I could run it in one Firefox tab or distribute the load across multiple tabs (if that's better). I was ...
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Homogeneous cores and heterogeneous cores

I am currently reading up on multi-core architecture for CPUs. However, I am having difficulties understand the meaning of "using one core design repeated consistently" which describes homogeneous ...
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Can I tell how much multi-threading I'm using each day?

Is there a way to determine (or even better, to log) how much benefit I'm getting from my computer's multi-threading capabilities? Background: My higher-ups are proposing to give me and my team new ...
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Can Intel CPUs change clock speed on a per-core basis?

Many multi-core Intel CPUs feature both SpeedStep and Turbo Boost, and can therefore run at clock speeds both below and above their base frequency. Can these CPUs control the clock speed per-core, or ...
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Parallel: Limited number of multi-threaded processes

I'm using GNU parallel to run multiple jobs in parallel like this: parallel python3 main.py arg ::: args*. With single-threaded jobs, I used -j 100% to ensure that 1 job is mapped to 1 core. Now, ...
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Why do we have CPUs with all the cores at the same speeds and not combinations of different speeds?

In general if you are buying a new computer you would determine which processor to buy by what your expected workload will be. Performance in games tends to be determined by single core speed, whereas ...
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Is it possible to simulate a singlecore CPU in a multicore CPU?

I have a multicore CPU with Windows 10 and I would like to test a Software running as if my PC was a singlecore CPU. Is there any way to limit Windows 10 installed in a multicore CPU (Quad Core) to ...
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505 views

How do you control thread affinity across multiple processes on Linux?

Question How do I run two benchmarks such that: They are both executing concurrently Both benchmarks have half their threads on each socket. No two threads share the same core. Background I have ...
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1answer
60 views

Why does everything I do seem to use all my CPU cores?

I have an Intel i5 4300m. When I open the Windows Resource Monitor, it shows 4 cores. When I perform operations such as using the browser or running a simple Python script, the % usage of all 4 cores ...
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Does 'make' take advantage of multiple cores/threads? (linux)

We are considering a new workstation (will be running Fedora 25/26), and would like to know what a good CPU would be. To start off, I need to know how many cores I need. To help decide that, I want to ...
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Threads (versus cores) and rated CPU clock speed, what is the effect?

If my CPU is rated at 2GHz, and has 4 cores supporting 8 threads, are all 8 threads running at the rated clock speed? Or are they running at 1GHz each since there are twice as many threads as cores?
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How to log/get a report on threading performance in Windows?

So with programs like Process Explorer and Process Hacker you can see what the individual threads from a given process are up to. However as far as I can tell its just an active monitor with no way to ...
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271 views

ffmpeg performance with multiple core cpu and windows [duplicate]

I call ffmpeg command to generate mp4 using input of mp3 and folder of images my problem is running 3 instance of ffmpeg cause 8 GB 6 core to be full with 100% cpu this is the command I use , any ...
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Terminology for cores in a multicore processor [duplicate]

What is the difference between logical and physical cores in a multicore processor? And is execution core another name for a physical core?
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How much do IDEs take advantage of multiple CPU cores?

So, how much do IDEs, for instance Android Studio or Eclipse, take advantage of multiple threads and CPU cores? That is, how much faster do they run on, say, a quad-core CPU compared with a dual-core ...
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How can I change the distribution of Cores across NUMA-nodes?

On Ubuntu 14.04 TLS for 36 total cores = (2 x CPUs x 9 Cores x 2 HyperThreading), lscpu give me: Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little ...
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169 views

What Control unit has the power in a multicore cpu?

A processor with cores is just a bunch of single cpus thrown together on a single IC (Integrated circuit)(That's why my /proc/cpuinfo shows 4 of them). A CPU is made up of some sub-units always ...
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1answer
371 views

Parallel Programming in AMD based laptop

I've a Lenovo G50 series laptop with AMD A8-6410 @2Ghz, 8 GB RAM with a R5 230M and Radeon HD 8550M cards inside. In Windows 10 is it possible to run a CLI based program ( ffmpeg for video ...
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3answers
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Logical vs. Physical CPU performance

A computer has 2 physical cores, and 4 logical cores (For example, a computer with an i5-3210M processor). When a program A runs, htop shows that it uses 100% of 1 core, and other 3 cores are nearly ...
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How do Multi cores CPUs get tasked?

I have an AMD Octo core CPU. As I watch the CPU meter app, I am noticing that while all cores can have activity, it seems a couple have higher and more consistent activity. How does the "work load" ...
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1answer
96 views

Turn off cores in multicore processor

I have several home grown applications that run together, exchange data, and are time synchronized with each other. I've found that having the OS bouncing around between cores fouls up this ...
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1answer
993 views

Hyper-Threading (SMT) Affinity and Equality

This question goes out to the Intel gurus that I know are out there. Are both threads on a physical CPU treated equally? As we know, hyper threading on intel CPUs is a system in which each physical ...
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1answer
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CPU usage by Adobe Dreamweaver on a HP probook G1 450 - i5 Quad Core

Is CPU usage of 40% - 50% normal when running Adobe Dreamweaver CS6, or is there an underlying problem? My laptop is a HP ProBook G1 450, i5 Quad Core, and has 8GB RAM.
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540 views

How to disable some cores on Intel machine

I have a machine with two Intel(R) Xeon(R) CPU E5-2618L v3 processor, which has 8 cores on each socket. I only want the OS or hypervisor (such as Xen) on the machine to detect only one socket and ...
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Strange relation between processor cores usage and their temperature

I have a four core processor. When running office apps, all processor cores usage is about 1% and the temperature is about 32-38 degrees each. When running a specific game, core 1 works at 100% ...
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Is a single core process reassigned to some other core automatically when the core utilization is high in linux?

Generally, by default, if a single core process starts to have high core utilization, will it be reassigned to some other core which can handle and unless it is exclusively defined not to with in the ...
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Why multi core processors producing less heat

We are using multi core processors partially, because the waste heat of single core processors was to high to handle. (correct?) Now we are using multi core processors that create less heat and need ...
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2answers
963 views

ffmpeg encoding to VP9 results in Google Chrome-unplayable video, while to VP8 works

Plenty of time passed, since I have encountered the problem, specified in the subject. I tried multiple ffmpeg static builds, have built it from Git repository myself with different flags and on all ...
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2answers
1k views

Spread VirtualBox VMs over cores

I am using many VirtualBox VMs with different OS on one Ubuntu Linux host for development. Sometimes my scripts get wrong and starts loading 100% of VM cpu. And when one VM loads 100% cpu I cant even ...