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Linux Trace Toolkit supports real-time Linux

Aug 30, 2000 — by LinuxDevices Staff — from the LinuxDevices Archive — 3 views

Montreal, CANADA / Lindon, UT — (announcement) — Opersys, Inc. and Lineo, Inc. today announced availability of the Linux Trace Toolkit (LTT) for Real-Time Linux. Although LTT has been available for standard Linux user-space tasks for many months, it has only now been modified to provide the capability to trace real-time Linux tasks running in the kernel memory space. Like the expensive time-tracing solutions available for many proprietary embedded RTOS solutions, LTT provides developers with all of the information necessary to reconstruct a system's behavior over a certain period of time. Using LTT, one can graphically view the precise dynamics of a system, answering such questions as:

  • Who actually has access to the hardware during a specific time slice?
  • What happens to an application when it receives data?
  • Where are the I/O latencies in a given application?
  • When is a specific application actually reading from disk?
  • Why do certain synchronization problems occur?
LTT provides this related information through three primary graphical and text information displays which map the system's lowest level processes (such as scheduling decisions, process switches and various management tasks) to each high-level application — all plotted against the time axis. The event graph provides the viewer with a unique perspective on the flow of events in the system. Every control modifying event changes the appearance of the graph. The process analysis thumbnail provides the user with an in-depth analysis of every process that existed during the course of the trace.

The items displayed are the same for all the processes except process 0 (idle) which is called 'The All Mighty' and is used to display the summarized information about the whole system. The raw list of events is, as its name says, the raw list of events that occurred during the period of the trace. All the events are listed with the exact time at which they occurred, the PID of the process to which they belonged, the amount of space occupied by the event in the trace module in the kernel and the string accompanying the event, if any.


LTT is an open source project that is freely distributable under the GNU General Public License. Additional information and a download for LTT is provided from the Opersys LTT project page at This work has been performed by Karim Yaghmour ([email protected]), the chief architect of LTT and founder of Opersys, Inc., under funding by Lineo, Inc. A pre-patched version of LTT as well as other real-time Linux debug tools will be available in Q4 on Lineo's Embedix RealTime CD, which is currently undergoing beta testing. Watch forthcoming news releases for details.

Related stories:
Linux Trace Toolkit — GPL real-time trace support for Linux
Lineo releases Embedix RealTime, adds trace tool

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