Search this blog

The Kernel Kobject device model explained

The Kernel Kobject device model explained.

This article explains the glue that holds linux kernel devices and subsystems together.

Comments

Post a Comment

Product Buy

Popular posts from this blog

Writing a Poll Mode Driver (PMD) for DPDK

Image
Writing a PMD for DPDK As mentioned in the previous post in this series about  DPDK , I have shared how to prototype L2/L3 applications using DPDK library without any dependency on Hardware (Physical/Emulated). In this post, I share how to write a  PMD  ( Poll Mode Driver ) for DPDK, off-course, it will not cover all the enhancements and features present in industry grade drivers, which you can explore in the existing PMDs in the DPDK source. Advanced features include, queuing algorithms for QoS, Offloading features for Protocol offloading, Protocol Parallelization features. Here, we see how to write a PMD for a Network Interface Card, most commonly found on your Desktop/Laptop,  Realtek NIC  card. The Realtek NIC on the physical hardware is  8136 however, there is also a  qemu-kvm  based emulated NIC which can be configured on the virt-manager “ 8139 ”. Another emulated NIC  e1000  exists which also has DPDK support, which also hel...
Read more posts

The Experiential Trip - Ooty wild walking

Image
“… it resembles Switzerland, more than any country of Europe… the hills beautifully wooded and fine strong spring with running water in every valley…” —  John Sullivan If you hear the terms “Switzerland of India” or “Scotland of India” and think of them as marketing gimmicks by the tourism industry, then think again, because the above was quoted by an Englishman who was the founder of the British settlement of Ottacamund. He had set out to explore the Nilgiris to validate the fabulous tales that were circulating. He noted that the weather was healthy and unusually temperate, ideally suited as a “resort for invalids” for soldiers among British ranks. If you ask me, his words still echo after 250 years, and Ooty is popular among Banglorites, Westerners, and for people across India, even so more, it is one of the most sought after weekend destinations in south india. Texture wise its completely different from the more commonly construed south India panorama, ...
Read more posts

Jiffies and other Kernel globals

I recently had to create a alias for accessing the jiffies variable so this write up is regarding what I read and understood about jiffies and other global variables. Jiffies is a global variable declared in as: extern unsigned long volatile jiffies; Its only usage is to store the number of ticks occurred since system start-up. On kernel boot-up, jiffies is initialized to a special initial value, and it is incremented by one for each timer interrupt. As discussed in the previous post, since there are HZ ticks occurred in one second, and thus there are HZ jiffies in a second. HZ = no. ticks/sec jiffies = no. of ticks Now I needed to access this jiffies through our project specific alias: typedef long                    proj_clock_t; volatile proj_clock_t    *projhrt = (volatile proj_clock_t *)&jiffies; Also came across this nice person who has demonstrated ways to access any kind of system memory: https...
Read more posts