General :: 1:1 - What's Meant By There Is Kernel Level Thread For Each Pthread Created
Mar 11, 2011
I have gone thorugh some documents about pthread (NTPL ) in linux 2.6 kernel. As per that linux uses 1: 1 threading model and for each user level thread there is kernel level thread. Pthread_create uses clone system call to create a LWP and the kernel could treat that as a LWP and do scheduling and all .( different from linuxthread). My question is what's meant by there is kernel level thread for each pthread created. Can I see the kernel level thread if I call pthread_create using ps .
What exactly meant by 1:1 .I mean for each user level thread there is kernel level thread . If I make a system call from a thread does the OS services that action via kernel thread ( created using kernel_thread () or some other way ) internally ..
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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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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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May 3, 2011
I've been trying to understand pthread in C a little better. So I made a simple program that takes in a string from the command line and creates a thread to print the string. I've looked online and copied the basic concepts but there are something things I'm confused about. The programs works just fine, but I have questions. Here's what I have so far.
[Code]....
One thing I'd like to know is why the 3rd argument in the pthread_create function which is my SendMessage function needs to be typecasted to a void pointer and then send the address of the function. Also as for the 4th argument, I would see typecasting to void pointer in some of the pthread examples I saw online, but in my case I'm passing a char pointer, would this be correct? In which case would I ever want to pass a void pointer?
Do I need a pthread_exit(NULL) in my main and in the SendMessage function? If so, why? I added the sleep() function so that I could let the pthread_exit function in my SendMessage function execute first. I simply saw that the online examples on pthread had pthread_exit() in both locations.
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Jan 6, 2009
I want to know what are the advantages and disadvantages for accessing spi(serial peripheral inerface )from kernel level and user level. like methods of doing it, speed ,memeory utilization etc
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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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May 26, 2011
In playback application i guess "snd_pcm_lib_write1" is the function call used to write the audio data to sound card at kernel level.If that is true. how can i send the same audio data at kernel level to other system connected over LAN.
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Jan 15, 2011
hello everyone, im having a problem when my computer enters in the run level 4 as the default when i start slackware. The strange thing is that it not seems that is a X window problem, it looks like more like a configuration problem in some part of the kde script to initialize the log in, because if i manually start the X service it works fine, i dont know what is the source. Thank you in advance for the help.
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Dec 25, 2010
I am going to use "pthread_setaffinity_np" to bind a thread to a specific core. My application has two threads. I have used mutex to assign a specific id to each thread and then bind that thread to a core different from another core. but it seems that the os assigns both thread to one core.What should I do to bind each thread to a specific core?
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Mar 31, 2010
I would like to know what is the difference between -lpthread, -pthread, -lthread? Sometimes, I have been used -lpthread as a option of gcc. but I don't understand anything about the others.
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May 27, 2010
I have a directory that has a another directory inside it. The top directory is rather redundant since it only contains the one other one. Is there a way to delete the top level directory and have the contents simply "move up a level"?
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Oct 21, 2010
I am attempting to write a program using Festival as the TTS output. It is a weather system, so
1) takes raw data from sensors on the input.
2) converts it into a text message
3) let festival take the message and turn it into audio that I can then route out to the telephone system.
Here is my main block of code using festival:
[Code]...
I imagine some of my problem is being a C/C++ newbie, but is there anybody out there able to give me some hints? Maybe there is a different or better way to fork that process. My plan is to keep updating the buffer whose pointer is passed to the function process() with my serial port processing program in the main loop. I can protect it with a mutex during the festival_say_text() function, but otherwise it will be accessible.
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Jul 13, 2011
I am currently having issues with system freeze when unmounting portable hard drives. This happens almost every single time. Normal USB sticks are fine and do not produce the freeze. I am using kernel 3.0.0-rc6, however the issue also persists when switching back to 2.6.39. This is the error message i get when freeze occurs, reverting to terminal output:
WARNING! power/level is deprecated use power/control instead
Jul 13 18:26:49 destiny kernel: [ 6196.892776] Call Trace:
Jul 13 18:26:49 destiny kernel: [ 6196.892803] [<ffffffffa008feec>] ? scsi_setup_blk_pc_cmnd+0x15/0x104 [scsi_mod]
[Code]...
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Nov 4, 2010
I am writing a device driver and want to debug it using KGDB.Could anyone tell how to install and debug with KGDB on Linux 2.6.35 distribution?
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Jul 14, 2011
I am learning about net filters and I am practicing some sample programs on it. I am very new to this and I have a general query. I got the packet to a desired function using PRE_ROUTING hook. Now how do I frame a packet from this point? I am just trying to simulate a echo client server program in the kernel level using these hooks. Any useful info on sockets in the kernel level?
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Apr 27, 2010
Most kernels are written in low level programming languages such as C and Assembly. Would it be possible to write a kernel in a high level language such as Python? Many high-level languages are themselves written in C.
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Jan 20, 2011
We all know linux kernel base layer is made up of structures, in which every object of kernel is well defined. Structure members correspond to object properties required to define object behavior.
For example if we take case of File system.It composed of four objects , superblock objects, inode objects, file objects and dentry object.Each having well defined structure which is being operated by system call handler and by system call service routine in the kernel mode.
Now my question is even in kernel mode we do not have some mechanism by which we can get access to pointer of these structures.We have some macro.
If I want to manipulate structure on my on way, or performing some more operation defined by me.For example after the crash of Hard Disk Drive, having ext2/3 file system, If i want to know all the inode pointers, and block details.
Can I have some way out to do desired operation ??
mechanism to operate on these base label structures, even in kernel mode ..
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May 29, 2010
I tried to install NVIDIA audio drivers on fc10 (2.6.27.41-170.2.117.fc10.i686).
It ended up in this error.
I am attaching nforce-installer log for your details.
Code:
By default I can use internet (without network drivers installed), how is this possible? And why not audio?
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Apr 11, 2011
i am using windows 7 in my laptop and linux is installed on virtualBox but my problem is the screen is showing small in virtualbox is there any way to enalarge the screen to show like windows screen? i did before by using VGA setting but it made problem me i was not able to use GUI interface i meant graphics interface
it was just showing me Command Prompt.
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Aug 10, 2010
I've been able to kludge a kill script which finds the correct pid for the kdeserver (or gnome server) after my system comes up in run level 5 so I can drop back to run level 3 mode. Lots of experimentation showed me that using telinit 3 and telinit 5 would occasionally leave the video memory in a mess and I would have the black screen of death.
I set the security parameter setting to autologin for me since I am the only user of my machine, but I still have to kludge the default setting under sysconfig (the DEFAULT_WM) under Window Manager to pick a certain window manager, so it takes time to manually switch the desktop.
Right now I can leave the gui and drop back to cli, but painful experimenting showed me that killing the X server is a no no. Right now I kill the kde server, which sends the SIGTERM to the X windows manager, which then figures out that it has to shut down.
Questions: Is there a better way of doing this? Apparently openSUSE figures that we have multiple users logging into the gui desktop, so the gui is always kept running and a login window with the desktop manager option forces the user to login in. With autologin, this never happens, but no choice of desktop is possible on the fly.
Can some type of script be set up to painlessly enable this to happen? And what is the best way of bringing either the Gnome or KDE desktop manager down gracefully? I do get lots of error messages as the system attempts to recover and X shuts down. It appears that apparently the single user with autologin is left out in the cold.
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Feb 6, 2010
I want to install a software called TinyOS which is an operating system designed for wireless sensor embedded networks in my account. The problem is it has instructions to install the software as an administrator since i'm not an admin of the department network i can not able to install. Is there any method to install this software as an user level rather than admin level.
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May 8, 2010
How can I adjust the levels at which the battery is considered to be critically low?ight now it seems this is set at 5 or 10%. I want to make it 20 or 25%This is for Gnome. I am using Lucid x86
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Jul 17, 2010
I accidentally did a 'chmod +x foo' when i meant to do a 'chmod a+r foo'.
-rw-r--r-- 1 casper trad 53 Jul 17 22:41 filegore
-rw-r--r-- 1 casper trad 13 Jul 17 22:41 filelemme
-rw-r--r-- 1 casper trad 24 Jul 17 22:41 nix
[code]....
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Aug 1, 2011
I'm a little bit confused with partitioning the filesystem in Linux. the difference between creating the file system with fdisk and mkfs (when formatting the disk). I can't clearly tell my problem, so please look at this picture:
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Jun 27, 2011
i wanna know what is my console, the terminal, pseudo terminal, thses things seem one thing to me ,, plz can anyone differentiate them. and how many consoles and terminals i have in slackware.
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Jun 28, 2010
What is meant by "stable" and "conservative"? I hear these adjectives get used a lot in reference to Debian. Does it translate to less buggy, less crashes and lagging behind in out-of-the-box support of new hardware?I noticed of all the distros for example, that my Wacom Graphics Tablet couldn't plug and play with Debian.
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Jan 24, 2011
I'm wondering if there's a way for me to install Ubuntu on a hard drive that I'm shipping to my brother. He has a different system and I'm sure it has some proprietary things that I'll need to set up. This is his first Linux system so I just want it to be ready to go when I ship the drive to him. I also don't want the install to take over my boot loader for my system...I am yet to successfully fix a boot loader after I screw it up (I know it's possible but I always just reinstall) and this time around, I'm hoping to avoid doing
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Feb 11, 2011
I wrote a code .sh I want to make it a runnable thread.
Q1: How can I do that in Ununtu?
Q2: I put that file (x.sh) in the "Auto start" program.I choose start at "start up" but it open the code editor page.I want it to be run behind backgroun...Have I convert it to .exe firstly ?!
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Feb 25, 2010
Is there a way for members to make a thread with a poll? I've looked around and havent found how, but thought it is around here somewhere.
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Jul 2, 2010
remove the thread after some one tells me.
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