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0
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0answers
18 views

Run GNU Octave script on multiple cores

I am computing Monte-Carlo simulations using GNU Octave 4.0.0 on my 4-core PC. The simulation takes almost 4 hours to compute the script for 50,000 times (specific to my problem), which is a lot of ...
20
votes
5answers
2k views

How to run a command at an average of 5 times per second?

I have a command-line script that performs an API call and updates a database with the results. I have a limit of 5 API calls per second with the API provider. The script takes more than 0.2 seconds ...
0
votes
1answer
30 views

Multithreading (increasing the number of threads for the process)

I wonder if there is any way of adding thread to specific process just to prove that number of thread which are assigned to process can be changed by user. If so, how could I do that ? [root@195689 ...
5
votes
2answers
17k views

Default stack size for pthreads

As I understand, the default stack size for a pthread on Linux is 16K. I am getting strange results on my 64-bit Ubuntu install. $ ulimit -s 8192 Also pthread_attr_init(&attr); ...
0
votes
0answers
180 views

FATAL: ThreadSanitizer can not mmap the shadow memory (something is mapped at 0x2ba33adb9000 < 0x7cf000000000)

I am trying to use thread-sanitizer functionality in my code .For doing so I have used following script : g++ -Wreturn-type -fmessage-length=0 -std=c++11 -c -O2 -fno-strict-aliasing ...
2
votes
1answer
83 views

Multi processing / Multi threading in BASH

I have a test file that looks like this 5002 2014-11-24 12:59:37.112 2014-11-24 12:59:37.112 0.000 UDP ...... 23.234.22.106 48104 101 0 0 8.8.8.8 53 68.0 1.0 1 0.0 0 68 0 48 Each line contains a ...
2
votes
1answer
41 views

Use multi-threaded make by default?

Is there any way to have make use multi-threading (6 threads is ideal on my system) system-wide, instead of by just adding -j6 to the command line? So, that if I run make, it acts the same as if I ...
0
votes
2answers
59 views

Need to format 5 disks in parallel

I tried this xargs -p 5 -n1 mke2fs -t ext4 /dev/sd[d-p]1 and got this [/dev/mapper]# seq 1 15 | xargs -p 5 -n 1 mke2fs -t ext4 /dev/sd[b-p]1 5 -n 1 mke2fs -t ext4 /dev/sdb1 /dev/sdc1 /dev/sdd1 ...
1
vote
2answers
64 views

Can a single core of a cpu process more than one process?

This is the reasoning for my question is what I read in a text book which states: Each CPU (or core) can be working on one process at a time. I'm assuming that this used to be accurate but is no ...
2
votes
0answers
56 views

Is using threads still considered an anti-pattern? [closed]

Background In The Art of Unix Programming, Eric S. Raymond dismisses multithreaded programming as a performance hack that should be avoided. According to him, the biggest problem with threads is that ...
1
vote
1answer
839 views

unpigz (and untar) to a specific directory

I know how to gunzip a file to a selected location. But when it comes to utilizing all CPU power, many consider pigz instead of gzip. So, the question is how do I unpigz (and untar) a *.tar.gz file ...
0
votes
0answers
18 views

Who controls the thread activity?

I know that there is a program called scheduler which controls the process activity within a system. But which part of the system controls the activity of threads within a process? By the way, do or ...
0
votes
0answers
31 views

Where are thread stacks located in user space?

Let's assume a single threaded-process sets the (user)stack at the end of its assigned userspace (e.g. 1GB) and it starts growing closer to the heap (1GB --> 0). How would it work in a multi threaded ...
1
vote
1answer
795 views

Running a python script 200,000 times in parallel using bash [duplicate]

I need to run my Python script 200,000 times. Is it possible to do parallel execution using bash? Since it's 200,000 times I would like to use at least 10 threads simultaneously
-1
votes
1answer
66 views

Why an LWP (Light Weight Process) is required for each concurrent system call in many to many thread model?

An LWP is a data structure placed between user thread and kernel thread, an appears as a virtual processor to user thread library. So, the minimum number of LWP required in many to many model of ...
0
votes
0answers
42 views

What are scheduler Activations?

I am reading about multi-threading in Peter Baer Galvin's Operating System Concepts; I don't understand the following topics: How LWP (virtual processor) works and schedules threads or maps to ...
1
vote
0answers
272 views

What happens to a multithreaded Linux process if it gets a signal?

If a Unix (Posix) process receives a signal, a signal handler will run. What will happen to it in a multithreaded process? Which thread receives the signal? On my opinion, the signal API should be ...
1
vote
1answer
95 views

Threads vs interrupts

What does it mean when threads are time-sliced? Does that mean they work as interrupts, don't exit while routine is not finished? Or it executes one instruction from one thread then one instruction ...
0
votes
1answer
42 views

Two or more threads on single core [closed]

What are the advantages of using threads on single core, does that makes sense to use multithreading on single core?
0
votes
2answers
123 views

When was the threading implemented in unix?

Which is the first Unix version or Linux version which implemented threads. And in which version bound and unbound threads were implemented? I know that in current Linux version threads are unbound by ...
1
vote
2answers
4k views

System sending SIGTERM and SIGKILL during normal work

I have a program (C++) that works with TCP sockets in multithreaded manner. The multithreading is intensive, about 100 threads (POSIX threads). Sometimes, not quite sure when, the program gets ...
0
votes
2answers
46 views

Plain installation vs Virtual machines - what is better for multicore? [closed]

We've currently bought a new server, with 64 GB of RAM and 8 cores with hyperthreading support. We are going to build a system using: nginx. apache. mysql. php So, the question is about ...
3
votes
1answer
552 views

Is vim multithreaded?

I have a HUGE (and I mean huge) text file that I am going to process with vim. I could process it using two different (debian) machines. One is duel-core and one is octo-core. A single core on my ...
1
vote
1answer
293 views

Limit max thread use for multithreaded java app

I have downloaded a .jar file and am using java with it, and it seems multithreaded, which is great ... unless I don't want it to be multithreaded, or unless I want to use only N threads with it. Is ...
1
vote
1answer
204 views

Set ionice for a multi-threaded application

I have a program that spawns multiple threads, all of which do fairly intensive IO, running on the background. I want to set the scheduling class to idle so that it doesn't clog up the system; ...
3
votes
2answers
2k views

Speed up zgrep on a multi-core computer

I'm running zgrep on a computer with 16 CPUs, but it only takes one CPU to run the task. Can I speed it up, perhaps utilize all 16 cores? P.S The IO is just fine, I could just copy the gzipped file ...
2
votes
3answers
447 views

Is any part of the X.org software multithreaded?

None of the command-line shells that I am aware of are multithreaded. In particular, even those shells that support "job control" (Control-Z, bg, fg, etc) do so via facilities (namely, fork, exec, ...
2
votes
2answers
85 views

how to workaround a deadlock (multithreading a program)

I need to run a program 100 times, a few hours each, which is fine when running it in a serial way, just takes very long, but when I try to parallelize it using GNU parallel or simple '&' in bash, ...
3
votes
1answer
449 views

What makes the Linux scheduler seem unpredictable?

The question refers to the output of a multi-threaded application, where each thread merely prints its ID (user assigned number) on the standard output. Here all threads have equal priority and ...
6
votes
3answers
6k views

Multithreaded cp on linux? [duplicate]

Is there a multi-threaded cp command on Linux? I know how to do this on Windows, but I don't know how this is approached in a Linux environment.
0
votes
2answers
430 views

won't the ever changing affinity assigned to threads by the Linux kernel have adverse effect on overall performance?

In my program, I have several threads that are started with the process and that remain until the program ends. They will meet different loads during the lifetime of the app, and at times they will ...
5
votes
3answers
14k views

How to call a service URL from bash shell script in parallel?

I have a service which I am calling from another application. Below is my service URL which I am calling - http://www.betaservice.domain.host.com/web/hasChanged?ver=0 I need to do some load test ...
7
votes
1answer
10k views

Multi-Threading/Forking in a bash script

I have written a bash script which is in following format: #!/bin/bash start=$(date +%s) inFile="input.txt" outFile="output.csv" rm -f $inFile $outFile while read line do -- Block of Commands ...
6
votes
2answers
2k views

What is the need of the struct thread_info in locating struct task_struct?

While reading through the Linux Device Drivers, I could understand that the Process Descriptor (of type struct task_struct) has all the info regarding a particular task. The process descriptors are ...
3
votes
3answers
15k views

How to launch two threads in bash shell script?

I am trying to copy files from machineB and machineC into machineA as I am running my below shell script on machineA. If the files is not there in machineB then it should be there in machineC for ...
2
votes
3answers
145 views

Linux - preventing an application from failing due to lack of disk space

Due to an unpredicted scenario I am currently in need of finding a solution to the fact that an application (which I do not wish to kill) is slowly hogging the entire disk space. To give more context ...
1
vote
1answer
232 views

How to copy in two folders simultaneously using GNU parallel by spawning multiple threads?

I am trying to copy files from machineB and machineC into machineA as I am running my below shell script on machineA. If the files is not there in machineB then it should be there in machineC for ...
3
votes
1answer
89 views

Is each process considered a thread?

Is a Linux process considered a thread? For example, if I write a simple c program that calls pthread_create to create a new thread in main(), does that mean that I now have 2 threads, one for ...
1
vote
2answers
526 views

How to copy three files at once instead of one file at a time in bash shell scripting?

I am running my shell script on machineA which copies the files from machineB and machineC to machineA. If the file is not there in machineB, then it should be there in machineC for sure. So I will ...
2
votes
1answer
138 views

Multiplex bash function execution

I created a bash function to "automagically" connect on our switches and retrive their startup-config using the expect command. I have to use expect because this switch does not accept the ssh ...
0
votes
2answers
503 views

Make Ubuntu acknowledge that a custom built version of PHP is installed

I'm trying to install PHP from source code on my Ubuntu 12.04 VPS. I'm installing PHP like this: Download the latest version from the php.net website. Configure it using the parameters below. ...
1
vote
0answers
1k views

What exactly is the lwp and threads in solaris?

The book "Solaris Internals" says Solaris executes kernel threads for kernel-related tasks, such as interrupt handling, memory page management, device drivers, etc. For user-process execution, kernel ...
2
votes
1answer
1k views

Running a process multiple times at the same time

I have a c++ program with opencv library which takes an image as input and perform pose estimation,color detection,phog. When I run this program from the command line it takes around 4-5sec to ...
7
votes
3answers
5k views

Why do top and ps show different PIDs for the same processes?

When I run top -H, I see that my multiple mysql threads all have the same PID. However, in ps -eLf I see each one has a different PID: ps -eLf UID PID PPID LWP C NLWP STIME TTY ...
2
votes
1answer
1k views

Which system calls could create a new process?

When executing ps command in my Linux system i see some user processes twice (different PID...). I wonder if they are new processes or threads of the same process. I know some functions in standard C ...
1
vote
3answers
478 views

can the “cat” command use multi-processes

I need to merge bunch of files in a directory on a unix box that has 8 cores. I am looking for a fast way to merge these files. The cat command uses only one core... is there a way where I can make it ...
16
votes
6answers
17k views

Why using more threads makes it slower than using less threads

Tried to run program X using 8 threads and it was over in n minutes. Tried to run same program using 50 threads and it was over in n*10 minutes. Why does this happen and how can I get optimal ...
2
votes
0answers
122 views

multithread handling in AM1808 using embedded Linux

I am using AM1808 ARM9 based board using GCC compiler (UBUNTU 10.04) . I am using Sqlite3 database management. I have some requirement regarding handling threads in background having access on ...
2
votes
0answers
221 views

So the design of client-server separation is not the bottleneck of X Window?

In the answer of this, it mentioned: People also hear that X uses the "network" and think this is going to be a performance bottleneck. "Network" here means local UNIX domain socket, which has ...
6
votes
2answers
15k views

Linux max threads count

my server has been running with Amazon Ec2 linux. I have a mongodb server inside. The mongodb server has been running under heavily load, and, unhappily , I've ran into a problem with it :/ As known, ...