How to use LTTng with TimeStorm
LTTng, the Linux Trace Toolkit Next Generation (LTTng), is a highly efficient full system tracing solution. It is composed of several components to allow tracing of the kernel, of userspace, trace viewing and analysis, and trace streaming. LTTng provides an integrated interface for both kernel and user-space tracing. A "tracing" group allows non-root users to control tracing and read the generated traces. It is multi-user aware and allows multiple concurrent tracing sessions. For more information, please refer to https://wiki.eclipse.org/Linux_Tools_Project/LTTng2/User_Guide
Note: You must have LTTng installed on target for remote tracing. For installing LTTng on the remote target, please refer to https://linuxlink.timesys.com/docs/wiki/engineering/HOWTO_Use_LTT
This document will show How to Use LTTng with TimeStorm. To run LTTng in TimeStorm follow the below steps.
- Set up a system based LTTng tracing configuration for a remote target
- Importing Trace data from the target to TimeStorm
- View and analyze Trace date
1. Set up a system based LTTng tracing configuration for a remote target:
A TimeStorm System Tracing Configuration is a collection of settings that are required to trace the system. The TimeStorm System Tracing configuration is persistent and can be launched multiple times to trace the system. To trace the whole system you have to set up a system-based Trace configuration for a remote target.
Select the LTTng → TimeStorm System Tracing Configuration option from the top menu to create the LTTng configuration for remote as shown below.
Double click on the TimeStorm Lttng Remote option on the left menu, which will create an entry under TimeStorm Lttng Remote category with the “New_configuration” as shown below.
The Timestorm System Tracing Configurations entries are categorized under different tabs on the right-hand panel and are explained below. To trace the system, mostly you have to just select the remote target on the target tab, create/select the existing session on the session tab, select events in the Events tab, and click the Launch button.
1. Target tab:
The Target tab shown below, allows you to select the hardware target used for system tracing.
In the Target tab, use the drop-down list to select a hardware target that you have already created. If you have not yet created a hardware target or want to change the settings for an existing target, click ‘Manage targets’ to open the Hardware Targets management utility. For more information, please refer to How to manage Hardware Targets.
2. Session tab:
Almost all the LTTng control operations happen in the scope of a tracing session. The existing sessions on the remote target are loaded to the Existing Sessions dropdown. If you want to create the new session, check the Create new session check-box and enter the session name in the textbox and click on Ok button will create the session in the remote target and load to the Existing session dropdown. Select the session in the Existing Sessions dropdown as shown below.
3. Events tab:
The list of Kernel events are displayed in the Events tab. Select the events which you want to trace as shown below.
For more information on Events, please refer to the https://lttng.org/docs/v2.10/#doc-enabling-disabling-events
After setting the values in all the tabs, click the Launch button at the bottom of the Tracing configuration dialog. This will connect your host to your target and start the tracing process and display the LTTng Profiling dialogue.
In the LTTng Profiling dialogue has following buttons;
Import button: is to download the tracing data from the remote target to TimeStorm.
Start button: is to start the tracing process for the session on the remote target.
Stop button: is to stop the tracing process for the session on the remote target.
Destroy button: is to destroy your session after you are done with tracing.
Cancel button: is to cancel the LTTng Profiling dialogue.
2. Importing Trace data from the target to TimeStorm
Stop the tracing session and click on the Import button to import the tracing data as shown below.
Select the trace and click on the Finish button to create the trace project with the session name in the Project Explorer as shown below.
To the view and analyse the imported trace data refer to Step 3 (View and analyze Trace date)
3. View and analyze Trace date:
After importing the Trace data, expand the Trace Project, and double click on the Kernel to view the results as shown below.
Statistics view: To view the data in Statistics, expand the trace session project --> Kernel --> Views --> Statistics
For more information on analysing the trace date and different views, please refer to the https://wiki.eclipse.org/Linux_Tools_Project/LT Tng2/User_Guide#Histogram_View.
