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Questions tagged [multiprocessor]

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How RAM is distributed among processes in MPI?

For example for a 4GB RAM and 2 processes, each process will take 2 GB of memory?
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Why do we use dynamic memory in ccNUMA systems when we talk about data distribution into locality domains by first touch policy?

In many books, when they talk about first touch policy in ccNUMA systems they are using dynamic memory allocation when they distribute data across locality domains. What if, for example, we have an ...
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Process freezes when using plotting with multiprocessing in Python

I'm parallelizing a process by using the multiprocessing module. The function that is parallelized does plotting and using savefig module saves the plot in pdf format. However, when the code is run, ...
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1answer
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How to get one core of a quad-ARM running without an OS

I'm using a quad-core ARM CPU and I'm wondering if it is possible to get 3 cores running in Linux, and one core running without Linux?
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1answer
106 views

Using CPU affinity with taskset to speed up Node.js computation, blocked for extended chunks of time

I'm running online servers for a physics-based game with a backend in Node.js. Currently, the server can handle 10 games/worlds at a time before the next tick needs to be executed. With this in mind, ...
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1answer
37 views

Is opening new tab equivalent to opening new window?

Is opening new tab in the terminal window is equivalent to opening a new tab in terms of resources? I need to run 16 scripts in parallel. I do not know whether opening tabs or new terminals is the ...
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1answer
34 views

Network addressing for multi-Processor Systems [closed]

I don't get how Network addressing works for Multi-processor systems. Check me out : Normal TCP/IP Networking uses The destination IP to designate the entire host/system, and the L4 (TCP/UDP) ...
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3answers
3k views

The number of processors and cores in my systems [duplicate]

This is the output of cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 78 model name : Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz stepping : 3 microcode :...
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1answer
599 views

How to split a file to multiple files with multiple threads?

So I have a 100GB text files And I want to split it into 10000 files. I used to do such tasks with something like: split -l <number of lines> -d --additional-suffix=.txt bigfile ...
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1answer
199 views

What is exactly happening in this process?

So I ran the following command and I accidentally saw the monitor and I wondered what is exactly happening. can someone explain to me what is exactly happening here? echo "`seq 100000000 -1 1`" > ...
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0answers
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determining number of free threads

Suppose that on a computer capable of processing n simultaneous threads, one wishes to launch n-m single-thread jobs where m is the number of threads currently in use. How is m defined and by what ...
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Optimal value for make -j <value> [duplicate]

What is the optimal value of the -j flag for make ? I know that all my source is free of errors. Is it the number of cores? Or the number of logical processors?
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Only one of the two processor cores is recognized by Linux Mint on my laptop

My computer seems to have only one of the two processor cores operating. inxi CPU~Single core Intel Core2 Duo T6400 (-UP-) speed~2000 MHz (max) Kernel~4.4.0-53-generic x86_64 Up~2:40 Mem~1180.8/...
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1answer
235 views

Parallelize recursive deletion with find

I want to recursively delete all files that end with .in. This is taking a long time, and I have many cores available, so I would like to parallelize this process. From this thread, it looks like it's ...
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1answer
26 views

Is it possible that the kernel doesn't let a already ready thread run even when there is a idle processor?

Suppose each thread's affinity is all the processors. Whenever a thread becomes ready, will the kernel attempt to find an idle processor to run it?
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1answer
8k views

What does “cpu MHz” field mean in the /proc/cpuinfo of a hyper-threading cpu?

The CPU is a i7-3770@3.40GHz. It has 4 cores and each core has 2 threads. Here is the dmidecode output: # dmidecode -t 4 # dmidecode 2.9 SMBIOS 2.7 present. Handle 0x0042, DMI type 4, 42 bytes ...
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Fast file access for many threads doing read / write operations?

I have a disk with a lot of data on it and I want to write some code such that thousands of threads can operate on the data. Each thread would work on its own individual file. This will speed up ...
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4answers
24k views

How to determine the maximum number to pass to make -j option?

I want to compile as fast as possible. Go figure. And would like to automate the choice of the number following the -j option. How can I programmatically choose that value, e.g. in a shell script? ...
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1answer
339 views

Is there a way to change the number of processors a program sees?

Is there any way I can trick a program into thinking the system has fewer processors? To explain: I am debugging a program that creates as many threads as it has processors, using sysconf(...
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2answers
2k views

Finding the CPU id numbers to use with cpu sets

The man for cpuset doesn't seem to clearly list how to figure out which numbers map to which processing units. My current machine has two Intel Xeon E5645s, each of which has 6 cores and ...
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1answer
532 views

What are the two sections of this dmidecode output?

I ran dmidecode on my system to verify certain processor information. However, I am not sure what the two sections of the output indicate. $ sudo dmidecode -t processor # dmidecode 2.11 SMBIOS 2.7 ...
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2answers
2k views

How does Debian make use of lots of CPU cores?

I just got an account on a 24 core VPS (according to UnixBench there are 24 CPUs). In general terms, how can I make good use of all these cores for general purpose shell computing in Debian? Do I ...
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4answers
99k views

So what are logical cpu cores (as opposed to physical cpu cores)?

I was googling about how I could find the number of CPUs in a machine and I found some posts but I am confused as some mentioned that you get the logical cores vs physical cores etc. So what is the ...
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2answers
3k views

what is meant by multiprocessing and how it works? [closed]

what is difference between cores, CPU, threads and processor on linux system ? please explain the difference
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1answer
1k views

Running one OS per core

I'm interested in using a COTS board like the Wandboard for a project. On one hand I'd like to use something like Ubuntu for user interaction, sounds, TCP/IP stuff, etc. But I also need an RTOS like ...
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0answers
1k views

Java uses max 8 cores on Debian, even though 16 are available [closed]

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. On the Debian machine, ...
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2answers
1k views

How to find out how many cores (including emulated via HT and such) are avaliable to user?

I wonder how to get how many cores (including emulated via HT and such) are avaliable to user via bash shell-script command?
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1answer
4k views

Should I disable hyperthreading when concerned about performance of single-threaded applications?

I use a i5-2410M processor, which is setup to do hyperthreading by default on my laptop. Considering that this is a 2-core processor, this means it can do 4 threads at a time. This also means that ...