A generic tracing API for Linux

Many userspace developers want a "flight recorder" for applications on Linux. While Solaris offers a comprehensive tracing tool, dtrace, Linux is now growing pieces of tracing functionality.

In user space, the trace information will show up under /debug/root/name, where debug is the debugfs mount point, and root and name are the directory names passed to trace_setup(). The file state can be read to get the current tracing state; an application can write start or stop to this file to turn tracing on or off. The file trace0 is the relay channel where tracing data can be read; on SMP systems with per-CPU channels there will be additional files (trace1...) for additional processors. The file dropped can be read to see how many trace records (if any) have been dropped due to buffer-full conditions.

All told, it is not a particularly complicated bit of code. Perhaps the most significant feature of this patch is that it is part of the infrastructure created and used by the SystemTap project. Getting this code into the mainline will make it that much easier for distributors to provide well-supported tracing facilities to their users. And that, in turn, should make users happy and give analysts one less thing to complain about.

Join the PC World newsletter!

Error: Please check your email address.

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Jonathan Corbet

Show Comments

Most Popular Reviews

Deals on PC World

Deals on PC World


Latest News Articles


GGG Evaluation Team

Kathy Cassidy


First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni


For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell


The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi


The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott


My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.


Latest Jobs


Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?