Programming :: Pthread - Optimize Computing Function / Loop With Threads?

Sep 4, 2010

I have to compute prime numbers with threads in C. So I choose the algorithm "Sieve of Eratosthenes" and I tried to create 2 threads, but I don't know how to optimize my computing function with threads I beg for help. This is my function:


but it seems like the both of the threads are calculating the same function twice? Is it possible to be optimized or not?

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Programming :: Remote Function With Pthread?

May 22, 2010

I wrote some code in c, using pthread (I configured the linker and compiler in eclipse IDE first).

Code: #include <pthread.h>
#include "starter.h"
#include "UI.h"
Page* MM;


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Programming :: Pass Arguments To A Function Using A Loop

Mar 1, 2010

I need to pass a large number of arguments to a function which takes variable number of arguments, such as gtk_list_store_new. But it doesn't look nice if i write something like gtk_list_store_new(NUM,TYPE_A,TYPE_B,TYPE_C,...,TYPE_OMEGA); because of large number of arguments. And, it will be a trouble to change number of columns because of need to manually change arguments to large number of such functions. So, how can i pass all the arguments to a function using a loop? Something like


Of course, i could just use asm code for this, but is there a portable way of doing so?

P.S. i mean C language.

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Programming :: Conduct Parallel Computing On CUDA?

Jul 29, 2011

I came across some problems. I need to conduct parallel computing on CUDA. I input "uname -a"and read these: "Linux BXSJC #1 SMP Wed Jul 6 14:46:26 UTC 2011 i686 i686 i386 GNU/Linux". I use CUDAtoolkit 4.0. when I input: cd /home/bxsjc NVIDIA_GPU_Computing_SDK/C and "make -i ",the computer returns


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Programming :: Pthread Not Release Memory

Jan 1, 2011

I have faced a problem with my code (a small tcp server). After the thread returns, the memory not decreases, but when a new connection is made, memory not increases and the new connection initialize a new thread with a same thread id of the previous thread. When two connections are made at same time, two thread ids are created and when the respective threads returns the memory not decreases. The Valgrind indicates that not memory leak occurs, the pointers are released. Indeed, more memory are allocate when new thread id is created. i used gcc and debian.


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Programming :: Signal Handling In Pthread?

Mar 12, 2011

I have created a pthread, and installed a signal handler inside that, same way as we do in main( ) function. The thread's signal handler is a separate function. Surprisingly, it is not working, that is the thread's signal handler is not able to catch signals. Here is the code:

Code: #include <unistd.h>
#include <sys/types.h>
#include <stdio.h>
#include <signal.h>
typedef struct data


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Programming :: Pthread Memory Not Being Freed?

Apr 19, 2010

I have an application that has pretty large memory profile. The general program flow is as follows:

do 10 times:


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Programming :: Portable Pthread Library Out Of 10 Distros?

Mar 10, 2011

im writing a cross-platform software (linux/solaris/mac/bsd) so i was wondering, how portable is pthread library? out of 10 linux distros, how many will have it by default? and does it exists on mac/solaris/bsd by default? or user will have to install it?

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Programming :: Suspend/resume A Thread When Using Pthread.h?

Dec 14, 2010

I want to suspend/resume a thread. The library I am using is pthread.h.I am also running my application on linux.Is there any function in pthread. let me suspend a thread temporary?I have read a document in which it was mentioned thatthread does not support suspend/resume

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Programming :: Pthread Mapping From Compiler To Kernel?

Aug 20, 2010

I'm trying to figure out how pthreads are mapped from the compiler to the Linux kernel. The pthread prototypes are found in a compiler header file (pthread.h), yet the kernel would be responsible for scheduling the threads. So, how does the compiler resolve the pthread symbols at compile time?

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Programming :: How To Optimize The Shell Script

Jan 30, 2011

Go through the following script


for(( i=65; i<=90; i++ ))


This code creates a file in which it writes a huge amount or records. But it takes a huge amount of time. Is there anyway of optimizing it?

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Programming :: Pthread And Mutex With Short Unlock Time?

Jun 15, 2010

I am wondering if pthread could make that a single thread keeps the "mutex" all the time if the time it remains unlocked is very small.

while (1)
lock; do_task(); unlock();


I experiment the thread2 never getting access to the mutex and never printing the nice message. I would expect that once thread2 calls "lock", it would get the mutex as soon as thread1 calls unlock() but it does not seem to be the case. If I add a sleep of some microseconds (100) in thread1 after unlocking the mutex, it solves the problem.

Does anyone know if this behaviour is normal? Is there a way to configure my mutex so that thread2 receives it when unlocked?I use

pthread_mutexattr_settype(&att, PTHREAD_MUTEX_RECURSIVE_NP);
pthread_mutex_init(&handle, &att);

to create my mutex. I am running ubuntu 9.04

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Programming :: Use Pthread Scheduling Policy Without Root User?

Jan 12, 2011

I am working on a large program in C to run on Puppy Linux. I have multiple pthreads running. I want to be able to set the pthread SCHED_POLICY and priority in my program but I want a user to be able to run the program without root privilege.
Using a sticky bit and root ownership gives the user too much power because they will be able to write and compile their own scripts. Is there a way to use 'sudo' when I set the thread parameters from my program or something like this?

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Programming :: Unix Programming - Single Process That Does Not Start Up Any Other Threads

Sep 28, 2010

i want a process that can operate as both a TCP echo server and a UDP echo server. The process can provide service to many clients at the same time, but involves a single process that does not start up any other threads.

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Programming :: How Can A Friend Function Access A Public Function From A Base Class

Nov 16, 2010

#include <iostream>
using namespace std;


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Programming :: Passing Data From Interrupt Handler Function To Tasklet Function?

May 18, 2010

I am doing some Linux kernel programming for my research project. I need to record the timestamp (by using cpuid and rdtsc) when an interrupt handler (top half) is first invoked. Due to the time critical nature of the problem itself, I have to do the timestamping inside the interrupt handler itself (the first operation when the handler is called). However, I understand that tasks that are not so time critical should be deferred to a tasklet function (bottom half) for processing because other interrupts are disabled in a (top-half) interrupt handler. I am currently out of idea on how I can pass the timestamp information that I have obtained in the interrupt handler to the corresponding tasklet function.

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Programming :: Socket Server Using Pthread Doesn't Wait For Accept() Properly?

Apr 19, 2010

I'm building a simple(?) socket server using threads to serve up a few requests. The spec is such that I have to listen to three ports at once, so I decided to use pthread to create three separate threads that would wait for connections, then spawn new threads to handle them.

The problem is that when I do this, for some reason the program never enters the wait loop and instead terminates (All three threads did get created since the messages get printed properly.) It gets to the line which prints "???", but not the line after the accept() call.I don't see an open port when I check for one either so I'm 99% sure they're terminating.Basically I have a main() method which has three calls to pthread_create, which should result in three threads being run that all wait for connections (listenOnPort). After each thread creation I print some info to make sure it's actually being created.

By the way, when I just run listenOnPortwithout threading, the server appears to enter the loop correctly and seems to be waiting for requests. It's only when I run the functions as threads that the problem seems to happen.The source is attached below. Any help will be appreciated. Much of the code is borrowed from a website (I can't post it because I am new here.) You need not worry about the handler_ methods because those are just methods that are run by the threads themselves.

Also--the original source was in C and I changed it to C++. Should I just use C?
server.h Code: /*
* server.h


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Programming :: Rules To Set The Pthread Stack Size - Compute The Memory Needed By Each Thread?

Jul 26, 2010

i have an application that launches several pthreads, i know that the default size used by Linux is 8Mb for each pthread. However i would like to optimize the total memory usage by my application by decreasing the default stack size of each pthread to the needed resources. My questions:

- Are there any rules to set the pthread stack size.
- How to compute the memory needed by each thread.
- Is the malloc call inside a thread counted from the stack size of the same pthread?

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Programming :: How To Run The Threads Continuously

Dec 1, 2010

I have two threads & i want to run it continuously ,with while(1) it is possible . Is there any other way to run the threads continuously

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Programming :: Server With 2 Threads Per Client?

Nov 25, 2010

In all the examples I have found the server accepts the client's conection, proccess the data received and close the socket. In an very schematic way it would be something like:


select to see if there is data to read from socket fd
if there is something to read{


Should I use mutexs or semaphores to block the socket fd before read and write or it is not necesary?

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Programming :: Listing All Threads In A Process?

Dec 29, 2010

How to list all the threads spawned by a process?

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Programming :: Threads Not Getting Arguments Properly

Mar 26, 2011

I wrote a C program using Pthreads to compute the product of 2 matrices. Each element in the product matrix is computed in a separate thread. Eg: Thread (i,j) computes the element C[i][j] of the matrix C, where C=A*B. A is m*n, B is n*p, C is m*p. m,n,p are given as command-line arguments. A and B are initialized to random values from 1 to 10, while all elements of C are initialized to -1.But some threads do not get their arguments (i,j) correctly. So some elements C[i][j] still remain as -1, even after the program is over. My OS is Ubuntu 10.10 (Maverick Meerkat) 32-bit.I ran the program on another computer and it worked correctly. Is it due to a problem in the Pthreads library in my OS? Please help me. I have attached the source code.

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Programming :: CPU Sharing Between Process And Threads?

Mar 29, 2011

I have doubt regarding cpu sharing between process and threads.In my program iam creating 4threads=> 1 process+4 threads. How is cpu alloted to these all tasks. Is here process is getting cpu time like thread or having more cpu time than threads.

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Programming :: Data Transfer Between Threads?

Dec 14, 2010

In posix multi threading, how to send thread1 local data to thread2...?

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Programming :: Multiple Threads In Socket C++?

Nov 26, 2010

void* thread(void* arg)


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Programming :: Synchronize 2 Posix Threads ?

Mar 15, 2011

I have 2 threads and both of them are deleting memory at the end nedded by both.

My problem is that maybe it can happen that a thread start and finish before the other one starts and so it deletes the memory nedded by the other thread. How can I synchronize them so that this can't happend.

As a design my threads look like this:


The other thread looks the same, but this isn't unoff to stop thread1 to finish before thread2 starts.

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Programming :: Code Of Merge Sort With Threads In C?

Feb 17, 2011

Please I want Know the code of the Merge Sort with threads in C

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Programming :: Command For Seeing Number Of Threads Running?

Jun 8, 2011

IS there any command to see number of threads are running in a process .I have check ps -eLf but it wont show display for all the threads

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Programming :: How To Communicate Between Two Threads Using Message Queue

Jun 7, 2011

How to communicate between two threads using message queue?

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Programming :: Reduce Memory Cost Of Threads?

Jul 21, 2011

Fedora15 32bit. I write a test program, it creates new thread continually, the thread does nothing but sleep. I find virtual memory increases up almost 10Mb when a new thread is created. and when there's more than 200 threads, the virtual memory used by the program is 3Gb, and now cann't create new thread. but on windows, it costs little memory. What can I do to config the operation system to take less memory on threads?

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