Software :: Match Pid Value In Ps Output To Threads In Program?
Jul 20, 2010
I have a multithreaded program running. The threads are created by using pthread_create(). The ps shows a pid value for each thread in the process. The name of the thread is all the same as the parent process. I want to match the PID values in the ps output to the threads in my program. But when I used getpid() in each thread, the value I get is different from what ps shows. How do I match the pid value in ps output to the threads in my program.
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Jul 25, 2010
I am runig a program on a server at my university that has 4 Dual-Core AMD Opteron(tm) Processor 2210 HE and the O.S. is Linux version 2.6.27.25-78.2.56.fc9.x86_64. My program implements Conways Game of Life and it runs using pthreads and openmp. I timed the parrallel part of the program using the getimeofday() function using 1-8 threads. But the timings don't seem right. I get the biggest time using 1 thread(as expected), then the time gets smaller. But the smallest time i get is when i use 4 threads.
Here is an example when i use an array 1000x1000.
Using 1 thread~9,62 sec, Using 2 Threads~4,73 sec, Using 3 ~ 3.64 sec, Using 4~2.99 sec, Using 5 ~4,19 sec, Using 6~3.84, Using 7~3.34, Using 8~3.12.The above timings are when i use pthreads. When i use openmp the timing are smaller but follow the same pattern.I expected that the time would decrease from 1-8 because of the 4 Dual core cpus? I thought that because there are 4 cpus with 2 cores each, 8 threads could run at the same time. Does it have to do with the operating system that the server runs?
Also i tested the same programs on another server that has 7 Dual-Core AMD Opteron(tm) Processor 8214 and runs Linux version 2.6.18-194.3.1.el5. There the timings i get are what i expected. The timings get smaller starting from 1(the biggest) to 8(smallest excecution time).The program implements the Game of Life correct, both using pthreads and openmp, i just cant figure out why the timings are like the example i posted. So in conclusion, my questions are:
1) The number of threads that can run at the same time on a system depends by the cores of the cpus?it depends only by the cpus although each cpu has more than one cores? It depends by all the previous and the Operating System?
2) Does it have to do with the way i divide the 1000x1000 array to the number of threads? But if i did then the openmp code wouldn't give the same pattern of timings?
3)What is the reason i might get such timmings?
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Apr 30, 2010
I have created a simple download schedular with source-code give below :
---------------------record_strokes.sh-------------------
touch /home/student/packs/lynx/logfile
lynx -cmd_log /home/student/packs/lynx/logfile
[code]....
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Sep 22, 2010
I wrote a program that multiplies 2 matrices using multi-threads and another one using multiple processes and shared memory. Both in C.I need to find the total memory usage of these programs. I know of the top command, but when my matrices are relatively small they don't even show up on top because they complete so fast, how can I find the memory usage for these instances?Also, how can I find the total turnaround time of my programs
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May 12, 2010
Is their a program in ubuntu that can match adobe acrobat 9 pro extended?Or what is the best ubuntu PDF program, that can allow the most features seen in adobe acrobat 9 pro extended.
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May 21, 2010
I have Ubuntu 9.10 running on Dell Dimension 8400, 1 gig ram, Pentium 4. No other OS installed. Last night I decided to upgrade from 9.10 to 10.0.4 through Upgrade Manager with the upgrade button. The upgrade ran over an hour and errored in the "Installing the upgrades" step with the following messages on the Terminal screen:
"rpmdb: Program version 4.8 doesn't match environment version 4.7.
error: db4 error (-30971) from dbenv->open: DB_VERSION_MISMATCH: Database environmnet version mismatch
error: cannot open Packages index using db3 - (-30971)
RPM failed to open database, cleaning it up..."
I went to bed without doing anything. This morning at 7:30am EST I checked the status of this and nothing changed to the screen it was still stuck on this error with progress bar at 4 minutes in Upgrade Manager. I can move my mouse and even open Firefox 3.6.3 to search for issues within Ubuntu environment so I am not frozen. I haven't tried anything else yet.
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Jul 11, 2011
I have a weird/stupid question. How do you know what command would start an application after installing it, if the synaptic package name doesn't match?
For example google chrome and lmsensors. The first appears as Chrome in Synaptic and the second as lmsensors, but to run them you have to type google-chrome for the first and sensors for the second in the console to start them.
When I did locate sensors or locate chrome/chromium, nothing came up in the search that would hint me that I need to run those commands. I had to rely on a google search and look for someone else's answer. Is there a better way, one that I can figure it out on my own?
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Oct 21, 2010
I have the following query:
Code:
$sql="SELECT table1.datetime, table1.user_id, table2.ip, FROM table1,table2 WHERE id='$id' AND (table1.id = table2.id AND table1.datetime = table2.datetime)";
In table2 the datetime fields are about 1 to 2 seconds off due to the source of the data, which I cannot change.
Is it possible via a query match table1.datetime & table2.datetime by HH:MM (ie. to the minute instead of to the second)?
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Jun 8, 2009
See the first program below :
Code:
This code when compiled gives the following errors:
1. conflicting types for 'fun' at line no: 9
2. previous declaration of 'fun' was here at line no: 3
Why is this happening?
If i modify the above program as shown in the second program below:
Code:
This code when compiled gives no errors.
Why the difference occurs between the first and second program?
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Sep 8, 2010
while doing socket/network programming, i am getting SSH-2.0-openssh4.7 error, instead of showing day time of server.general description i have Linux Box, with the help of putty i am connecting from windows system to Linux box,no problem in loging,after typing program, i am running the program with gcc. when typing ./a.out, it is showing SSH-2.0-openssh4.7, actually it should display daytime from linux box in both tcp and udp.
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Apr 29, 2011
i use touch screen monitor .when some one touch on screen i want to wake up in my c program and i use this touch usb output for my prograam
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Jun 1, 2011
I'm looking for a program that will visualize anything that goes through my audio-output (in this case it's Spotify) and display it on the screen. Does this exist?
I'm running Ubuntu.
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Nov 29, 2010
I've made a LED gadget, which can light up LED patterns. It connects to serial port with RS232 protocol and receives messages which contain desired patterns. My friend wrote a python program which generates patterns and writes them to terminal. Everything is fine this far. I've made a bash script to run this program:
#!/bin/bash
python gen.py
and set it to autostart with:
chmod 755 scr.sh
mv scr.sh /etc/init.d/scr.sh
sudo update-rc.d scr.sh defaults
What I don't understand is - how do I redirect it's output to ttyS0 so that my device could catch generated data?
I've heard that in Linux every data stream can be redirected anywhere with '>>' in bash script. How do I do that? Can I, dunno, write something like this: python gen.py >> ttyS0 in shell script?
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Jan 8, 2011
Is there any way to select which output device a program uses? I notice many Ubuntu programs lack the choice to choose where the sound is outputted, for example Rhythmbox and Exaile.I have 3 sound outputs (Internal, PCI, HDMI) connected and I'd like to for example use the PCI card as default audio device but play music from Rhythmbox through the internal motherboard output.
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Feb 6, 2011
so i wrote myself a very simple hellworld program in c++
...the usual stuff
int main()
{
[code]...
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Aug 14, 2010
I am creating a 15 integer array which is input from the user and outputted for the.
Ex.
Enter the array values: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Your values are: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Code:
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Mar 18, 2011
I am learning Linux daemon programming and write a simple daemon program. The issue is no data is written to the log file (/var/tmp/simpledeamon.log) though the file is successfully created (it's file size is zero from ls -l output). Could someone kindly point out the error in my program,The code is based on the Devin Watson's article at Here is the code:
// simplydaemon.cpp
// A simple Linux daemon.
#include <sys/types.h>
[code]...
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Jun 29, 2011
I'm using Ubuntu and I'm programing with eclipse CDT. My goal is to execute a php file and read the output to my c++ program. To do so I thought I should use fork(), dup2() and execl. When in shell, the call "php myscript.php" worked just fine, but when in c++ I tried:
execl("usr/bin/php", "php", "home/geiger/workspace/SemiServer/server_content/myscript.php", NULL);
And it didn't work (the process wasn't terminated and I got no output). I tried different version of this call, like losing the "php" string and/or drop "home/geiger" from the path string, to no better result.
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Sep 15, 2010
The below program is giving unpredictable and wrong output when I compile with g++ under Ubuntu OS , tried with the complier avilable with Ubuntu 8.04 and Ubuntu 10.04 LTS.
But it works fine when complied and ran Redhat g++ 3.4.6
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May 22, 2010
I've got a C program that I've added some 'printf' statements to monitor a couple of variables. When I run this program manually or from a script, the output is displayed on screen. However, I need to change various variables in the 'test.c' file, run 'make clean' and 'make' a few hundred thousand times. I'm using a script to read the variables in and then using sed to do in-place edits of the file. Unfortunately, with this amount of iteration, it is getting rather tired!
Anyway, I've created a script that is working as long I respond to prompts. I've tried the following to no avail: Code: /path/to/script > /tmp/output /path/to/script > /tmp/output 2>&1 /path/to/script | tee (no output even after adding the -a option) In my C program, I have the following 'printf' statement: Code: printf ("variable1: $s variable2: $s",var1,var2); What am I missing? I've worked with redirection before and it's always worked out fine, but this one plain stumps!
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Jan 13, 2011
I have a program that writes to stdout. Is there a way that I can redirect the output to the linux diff command or do I have to write the output to a file and then compare that. For example I have a bunch of test input files for a program and the corresponding expected output in another set of files. And I'd like to do something like ./program < t1.input | diff t1.expected.
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Nov 27, 2010
Can someone recommend a good app to monitor the OUTPUT of my soundcard? I don't just want to look at the VU meter of my music player - i actually want to see what the soundcard is outputting. Windows drivers for my soundcard (Audiophile 192) had this ability, but I'm not sure what software to use in Linux.
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Sep 30, 2010
I have nine barcode scanners, each of whose input I want to send to a separate instantiation of a program I wrote. Each device shows up as /dev/hidraw_ (I'm using Ubuntu 10.4). The problem is that they all act as simple keyboard input, and I can't seem to redirect the output from one to a specific instance of my program. I've tried something like cat /dev/hidraw5 > ./myapp, and that doesn't work. I've tried actually opening the device in my program using open("/dev/hidraw5"), and it returns success, but subsequent reads don't do anything, and the scanner output is just printed to the console.
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Feb 23, 2011
Is there already a program that reads multiple pipes or file descriptors and writes to the standard output (not splitting lines).Like cat, but reading all files simultaneously and preserving lines.It is needed to avoid coding of select/epoll loops or using multithreading in simple programs. Like "select loop for bash".
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Jan 27, 2011
Can anyone tell me what the pros and cons are between heirloom-mailx vs mailutils? This is for ubuntu 10.04 LTS. AT this point my only purpose is to use the mail command line program to occasionally send log output to email aliases.
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Mar 1, 2010
I have an X11 GTK program, let's name it "foo".I would like to start it from command line, either from a text console, or from an ssh log-in. I want to run foo with Administrator privileges and in higher priority, and I need redirect standard output and standard error. Standard errors must go to syslog, except "libglade Warning" messages and empty line messages. Standard output is redirected to a file.I wrote a script, called "foo-start". The "foo" program must run continously, so the "foo-start" script should not wait for "foo"'s termination.The scrip actually looks likelike this:
cd "FOO'S DIR"
(sudo nice --10 ./foo --display=localhost:0 &) 3>&1 1>foo-output.log 2>&3 | grep . | grep -v lobglade-WARNING | loggerr -p local7.err -t foo &
[code]....
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Dec 19, 2010
I was installing a game on my netbook with wine and it seems that it's using both of the cpu threads.
Did wine fix the multi-thread bug?
EDIT:
Sorry to get anyones hopes up, but I did later find that I was misreading some data. When I saw it say 100% cpu usage I thought it meant both threads, but I later found out that it only applied to one thread.
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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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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:
Code:
client_thread{
select to see if there is data to read from socket fd
if there is something to read{
[code]....
Should I use mutexs or semaphores to block the socket fd before read and write or it is not necesary?
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Dec 29, 2010
How to list all the threads spawned by a process?
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