May 9, 2011

KGPU - GPU Computing Framework

KGPU is a project that aims to port GPU capabilities directly to the linux kernel. Utilizing CUDA or OpenCL, userspace application can offload calculations to the GPU card, however KGPU extends this now transparently to the kernel. As stated by the project’s site The idea behind KGPU is to treat the GPU as a computing co-processor for the operating system, enabling data-parallel computation inside the Linux kernel. This allows us to use SIMD (or SIMT in CUDA) style code to accelerate Linux kernel functionality, and to bring new functionality formerly considered too compute intensive into the kernel. ... Read more

September 14, 2009

qtcreator-collec2-ld-returned-1-exit-status

When facing this error… manually cd into the project QT folder and run “make”… ld would return the library name it isn’t able to locate. Example: [sourcecode=“bash”] [email protected]:~/Documents/Dev/QT-Progs/Test$ make g++ -Wl,-rpath,/opt/qtsdk-2009.03/qt/lib -o Test main.o testhello.o moc_testhello.o -L/opt/qtsdk-2009.03/qt/lib -lQtGui -L/opt/qtsdk-2009.03/qt/lib -L/usr/X11R6/lib -pthread -lfreetype -lgobject-2.0 -lSM -lICE -pthread -pthread -lXrender -lfontconfig -lXext -lX11 -lQtCore -lm -pthread -lgthread-2.0 -lrt -lglib-2.0 -ldl -lpthread /usr/bin/ld: cannot find -lfreetype collect2: ld returned 1 exit status make: *** [Test] Error 1 [/sourcecode] ... Read more

April 19, 2009

Dive into the I/O subsystems

I decided to write this article as to give a short intro, which I hope would help one another to dive into understanding but more tweaking the I/O scheduler for better computing performance. So what is the I/O scheduler… Talking about the I/O scheduler requires to immediately address the issue of I/O process execution on a system. Each action made by an application whether in a simple read/write manner, memory allocation in a nutshell creates an I/O request to the filesystem/virtual memory, which in return transmit the requests to the scheduler, who handles it back to the low-level device drivers… ... Read more

December 17, 2008

Strace - Reverse Engineering - System Calls

If there is one recurring problem that I often see gagging the forums is “Library missing”, or often “installed libraries which a program doesn’t find”. I decided to share a simple debugging technique which could save the day or even the hours… Google might not be the right choice all the time, when you have got strace at your finger tips. 1. System Calls To understand strace, you first need to understand what a system call is. ... Read more

October 26, 2008

Sqlite - install and hack fix

Weather it is installing a software or recompiling a package, dependencies/libraries problems are always around the corner to make the life of a sys admin more complicated than it is. This Howto is more of a fix type than an overview on how to configure Sqlite. One day I was confronted to the challenge to install sqlite on a server when I got this error after compilation “offset error” To fix the problem, I have edited the sqlite. ... Read more

October 14, 2008

How to create a linux system call

Creating a system call in the kernel to be used by a user-space application isn’t that exotic but requires three basic steps. The first step is to create the function, to update the header files and to update the system call table. We will create the function with the asmlinkage modifier, which tells the compiler to pass all function argument on the stack. A simple system call function could be ... Read more

October 10, 2008

Linux Devices - Tip1 - /dev/full

This is a humble series on linux devices. Writing to /dev/full fails and produces “a disk full” error sending errno to ENOSPC… ENOSPC is the error that signals that the device is full. Would you wonder what’s the use of /dev/full - well pretty obvious, just to test how program behaves if they run out of a space where they can’t write. Cheers,

October 8, 2008

Linus(x)'s rambling blog

If you are interested in Linux, you certainly would be interested in Linus, its creator. Linus still works as one of the kernel mainternair (yes! you got it! Linux isn’t RedHat, Debian but only the kernel).. anyway, to get more update on the geek’s life, follow this link http://torvalds-family.blogspot.com/ have fun reading,

October 6, 2008

10 advises for junior systems administrator

Understand Linux… Although you might not be expected at a beginner level to understand and remember all the system calls and alloc() of the kernel, it is very important for your sake and the sake of whoever you happen to work with, that you understand how the kernel boots, how the kernel manages devices, files/blocks and most of all how the underlying structure of Linux takes place. Many SysAdmin start working with Linux, without getting the basics… and I don’t mean ‘cp, mv etc…’, I mean… get a book and read! ... Read more