September 8, 2011

RedHat/CentOS 6 Xen Kernel RPMs

I have created a working Red Hat/CentOS 6 Xen Dom0 Kernel including backport patches. I had to hack to the blktap driver hooks to finalize support of the module due to the interface changes in the recent vanilla kernel. But all is working. [[email protected] ~]# uname -rsm Linux 2.6.32-131.12.1.el6.alouche.xen.dom0.x86_64 x86_64 [[email protected] ~]# xm list Name ID Mem VCPUs State Time(s) Domain-0 0 1024 4 r----- 235.5 For download of the RPMs or mirror use, see http://mirror. ... Read more

September 3, 2011

Padhye et. al. Equation and TCP performance

If you are not familiar with the Mathis Equation, I recommend you quickly go over my post article Mathis Equation and TCP Performance. This is necessary since the Padhye et. al. Equation is an extension to the Mathis Equation for accuracy of TCP throughput calculation over multiple scenario of packet loss. As simply put, the Padhye et. al. Equation Equation is exactly the same concept as the Mathis Equation but taking in consideration the Maximum TCP Window size affected by received/lost/duplicate ACK, the initial retransmit timer and the effect of the TCP timeout mechanism on the total throughput. ... Read more

August 6, 2011

pwgen 0.5 released

Hi there! I have just released version 0.5 of pwgen, which has been refactored to be Firefox 5 compliant. For those who wishes to use the addon prior to the review from Firefox Mods, you can download the version here. Russian and Polish languages have been added - Thanks to Artem Karpenko [email protected] (RU) and Slawomir Dal - [email protected] (PL).

July 18, 2011

The Kernel Samepage Merging Process

KSM, simply put is a service daemon which scans the page addresses to find duplicate pages, merges them and therefore reduces the memory density. The code used in this post as example can be found under /mm/ksm.c in the kernel source. Before continuing, it is important to keep in mind that: KSM uses a red-black tree for the stable and unstable trees - efficiency is $$O(\log\ n)$$ per tree since the height can never be more than $$(2log\ (n+1))$$ with n being the number of nodes. ... Read more

July 16, 2011

Small Blog Update

After spending 2 relaxing weeks abroad with crazy dolphins [slideshow id=1] here are 2 small changes to the blog: ####Introduction of short FAQ Posts### One could easily say that my blogging activity has been a logarithmic decrease per individual months ;-). Having not enough time to write lengthly posts, I will resort to write some FAQ related posts, short in length and to the point. Lengthly posts will still be on the menu but at least the blog will not be that periodically vacant as it has been ;-) ... Read more

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

April 1, 2011

kojid dead but subsys locked

I have been toying with Koji ( A build server by Fedora) and encountered an issue while starting the kojid daemon on one of the builder host. [[email protected] ~]# /etc/init.d/kojid status kojid dead but subsys locked while the log kept showing [INFO] Starting up Time for some debugging, I issue [[email protected] ~]# /usr/sbin/kojid --verbose --fg and see koji.AuthError: Traceback (most recent call last):` koji.AuthError: Traceback (most recent call last): File "/usr/share/koji-hub/kojixmlrpc. ... Read more

February 23, 2011

We geeks aren't rude

Much of what looks like rudeness in hacker circles is not intended to give offense. Rather, it’s the product of the direct, cut-through-the-bullshit communications style that is natural to people who are more concerned about solving problems than making others feel warm and fuzzy. Eric S. Raymond

February 14, 2011

Don't like make? Use ninja

ninja is a new build system developed by the Chrome developers at google, used to compile chrome executables Source code is available at: Blog post about ninja at: In a nutshell, ninja is a simple and light weight replacement to “make”… it is surely worth a look if you are looking for a fast lightweight build system alternative.