Give me another jiffy, only a bit later

Given the description below, jiffies + 10*HZ means (now + 10 Seconds). And jiffies * 1000 would mean the elapsed time in milliseconds etc.

An example of usage in the Linux Kernel would be in the drivers for XD, where, jiffies + 8*HZ later (as initialized in the member element expires of static struct timer_list) a timer interrupt handler is programmed to execute.

The “watchdog handler” xd_watchdog, in this particular instance, wakes up a sleeping process.

Needless to say, all appropriate caveats emptor apply. Appropriate Processes need to have been sleeping, Timers must have been declared and initialized etc etc

I will blog on this at length later. Please subscribe to our mail list for automated updates on new blog entries.

I explain this specific Linux Kernel concept and more in my classes ( Advanced Linux Kernel Programming @UCSC-Extension, and also in other classes that I teach independently). As always, Feedback, Questions and Comments are appreciated and will be responded to.


About Anand

Anand is a veteran of Silicon Valley with development experience and patents that span Processors, Operating systems, Networking and Systems development. Anand has been working for the past few years with Service Providers and large Enterprises developing e and Training systems.

No comments yet.

Leave a Reply