Feature #968: lttng-modules kernel and user callstack context - LTTng - LTTng bugs repository

Actions

Copy link

Feature #968

open

lttng-modules kernel and user callstack context

Added by Mathieu Desnoyers about 9 years ago. Updated over 1 year ago.

Status:

Feedback

Priority:

High

Assignee:

Mathieu Desnoyers

Target version:

Start date:

10/25/2015

Due date:

% Done:

Estimated time:

Description

Implementation from Francis Giraldeau reviewed and cleaned up available here:

https://github.com/compudj/lttng-tools-dev/tree/callstack
https://github.com/compudj/lttng-modules-dev/tree/callstack

Documentation and tests are missing.

Actions

Copy link

Updated by Jérémie Galarneau over 8 years ago

Status changed from New to Feedback
Target version changed from 2.8 to 2.9

Actions

Copy link

Updated by Erica Bugden over 1 year ago

Target version deleted (~~2.9~~)

Kernel and userspace callstack context fields for kernel events are available in LTTng 2.11. Userspace callstack information is currently only available for x86 32/64 systems.

From: What’s new in LTTng 2.11?

Two new context fields are available for Linux kernel channels:

callstack-kernel
callstack-user

Thanks to those, you can record the Linux kernel and user call stacks when a kernel event occurs. For example:

lttng enable-event --kernel --syscall open
lttng add-context --kernel --type=callstack-kernel --type=callstack-user

When an open() system call occurs, LTTng attaches the kernel and user call stacks to the recorded event.

Note: LTTng cannot always sample the user space call stack reliably. For instance, LTTng cannot sample the call stack of user applications and libraries compiled with the -fomit-frame-pointer option. In such a case, the tracing is not affected, but the sampled user space call stack may only contain the user call stack’s topmost address.

Actions

Copy link