Abstract Sometimes, we may want to migrate one process/thread to one specific CPU for some specific purpose. In the Unix/Linux systems, you may choose sched_setaffinity to finish this job. This article will help you to understand how sched_setaffinity (or other APIs like pthread_setaffinity_np in user-space) works internal Linux kernel. Details SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int,…
You may already well know “Linux” and may also use the “operating system based on the Linux kernel” directly or indirectly (you are indirectly using it now as this site is hosted on Linux). But how should we name the OS based on Linux? You may know there is GNU/Linux naming controversy. Different people have…
The Linux kernel has a generic driver for a graphic framebuffer named vesafb on intel boxes. It provides a nice large console for most of modern displays. Setting VESA modes for Linux kernel with 32-bit and 16-bit boot protocol are different. We introduce both methods here. Linux kernel with 32-bit boot protocol For machine with…
I ever introduced [[installing-xen-domain-0-on-fedora-17]] as the first try to use the xen package delivered from Fedora and get away from manually compiling Xen and patching the kernel. In this post, I introduce installing Xen Dom0 on Fedora 20. Installing Xen First, install the xen pacakges: # yum install xen The Linux kernel is already ready…
Before statically linking you C and C++ programs, you should be aware of the drawbacks of the static linking especially with glibc. There are some good discussions already: with glibc you’re linking static programs which are not really static and some others here and here. That said, you can choose to statically link C and…
The performance of Xen’s Dom0 is important for the overall system. The disk and network drivers are running on Dom0. I/O intensive guests’ workloads may consume lots Dom0′s CPU cycles. The Linux kernel calculates various network related parameters based on the amount of memory at boot time. The kernel also allocate memory for storing memory…
`diff` and `patch` are tools to create patches and apply patches to source code, which is widely used in the open-source world, such as Linux kernel and application. patch: applying patches To apply a patch to a single file: $ patch < foo.patch If the foo.patch does not identify the file the patch should be...
iptables is a mechanism in Linux kernel for port forwarding, NAT, firewalls etc. In Linux distros, such as Fedora, the iptables is configured to be as a “strict” firewall that opens a limited know ports, such as 22 for SSH. However, in some network environment, such as a private cluster, the nodes are trusted and…
The new development of Xen and Linux kernel make it easy to install Xen on Fedora as the Domain-0 now. This post uses Fedora 17 as an example platform to introduce how to set up Domain-0 on Fedora Linux. Compared to our old method (https://www.systutorials.com/setting-up-stable-xen-dom0-with-fedora-xen-3-4-3-with-xenified-linux-kernel-2-6-32-13-in-fedora-12/) which requires manually compiled Xen and patched kernel, the current…
The is a simple introduction to paravirt_ops in Linux kernel for Xen, VMware, etc. We make this introduction from the view of code. We use the function raw_local_irq_disable() and raw_local_irq_enable() functions in Linux kernel to introduce paravirt_ops for Xen and Xenified kernel. Please download the introduction to paravirt_ops pdf file: introduction-to-pv-ops-v3.pdf
This posts list benchmark (using bonnie++) result of I/O performance of Xen LVM and loopback backed VBDs. The configuration of machines Dom0 VCPU: 2 (Intel(R) Xeon(R) CPU E5520 @ 2.27GHz) Memory: 2GB Xen and Linux kernel: Xen 3.4.3 with Xenified 2.6.32.13 kernel DomU VCPU: 2 Memory: 2GB Linux kernel: Fedora (2.6.32.19-163.fc12.x86_64) DomU’s profile: name=”10.0.1.200″ vcps=2…
This is the latest stable and recommended stable Xen Dom0 solution on Fedora 12. No serious bug found till now and we will fix the bugs by ourselves if some appears. It also works on Fedora 14 as well. It should not be hard to use this solution on other versions of Fedora or other…
Here is a list of problem that may occur during installing and configuring Xen Dom0 in Fedora. It is found originally in Fedora systems, but the tips in this post should also be helpful for installing Xen Dom0 on other platforms. BIOS configuration If xen stops at: “I/O virtualization disabled.” We may need to enable…
The Xen solutions including installing and configuring Dom0 and DomU are summarized here. LVM volumes as backing for DomU’s file system is an appealing solution to Xen VBD. LVM volumes can dynamically grow/shrink and snapshot. These features make it simple and fast to duplicate DomU and adding storage to DomU. LVM backed DomU is recommended….
We may need to install some old packages such as the kernel in our Linux box. Let’s use installing a older version of Linux kernel in Fedora as the example to introduce how to install old packages from the repository using yum. By now, suppose we have install kernel-2.6.32.16-143 in the Linux box and we…
Linux port forwarding is simple to do with iptables which may probably already being used as the firewall or part of the setting up a Linux gateway. In the Linux kernel, port forwarding is achieved by packet filter rules in iptables. Port forwarding Port forwarding also called “port mapping” commonly refers to the network address…
How to set up eCryptFS in Linux will be introduced in this post. We can store encrypted files in one eCryptFS directory, the manual way. The content can be seen only after it is mounted as eCryptFS file system. Otherwise, the users can only see garbled characters in the files. Note that this tutorial will…
Please refer to for the latest stable Xen Dom0 solution. In this post, the detailed tutorial for setting up Xen 3.4.1 dom0 on top of Fedora 12 with kernel 2.6.29 will be introduced. Hardware: Dom0 hardware platform: Motherboard: INTEL S5500BC S5500 Quad Core Xeon Server Board CPU: 2 x Intel Quad Core Xeon E5520 2.26G…
Please refer to Setting Up Xen Dom0 on Fedora : Xen 3.4.1 with Linux Kernel 2.6.29 on Fedora 12 for the platform of this test (this test runs on Fedora 11, however). I have done some simple performance test on DomU and Dom0 and compare with the performance on physical machines. These test are simple,…