1 Yocto Project Profiling and Tracing Manual
Yocto Project bundles a number of tracing and profiling tools — this manual describes their basic usage and shows by example how to make use of them to analyze application and system behavior.
The tools presented are, for the most part, completely open-ended and have quite good and/or extensive documentation of their own which can be used to solve just about any problem you might come across in Linux. Each section that describes a particular tool has links to that tool’s documentation and website.
The purpose of this manual is to present a set of common and generally useful tracing and profiling idioms along with their application (as appropriate) to each tool, in the context of a general-purpose ‘drill-down’ methodology that can be applied to solving a large number of problems. For help with more advanced usages and problems, refer to the documentation and/or websites provided for each tool.
The final section of this manual is a collection of real-world examples which we’ll be continually updating as we solve more problems using the tools — feel free to suggest additions to what you read here.
1.2 General Setup
Most of the tools are available only in
sdk images or in images built
tools-profile to your
local.conf file. So, in order to be able
to access all of the tools described here, you can build and boot
sdk image, perhaps one of:
$ bitbake core-image-sato-sdk $ bitbake core-image-weston-sdk $ bitbake core-image-rt-sdk
Alternatively, you can add
tools-profile to the EXTRA_IMAGE_FEATURES line in
EXTRA_IMAGE_FEATURES = "debug-tweaks tools-profile"
If you use the
tools-profile method, you don’t need to build an sdk image —
the tracing and profiling tools will be included in non-sdk images as well e.g.:
$ bitbake core-image-sato
By default, the Yocto build system strips symbols from the binaries it packages, which makes it difficult to use some of the tools.
You can prevent that by setting the
variable to “1” in your
local.conf when you build the image:
INHIBIT_PACKAGE_STRIP = "1"
The above setting will noticeably increase the size of your image.
If you’ve already built a stripped image, you can generate debug packages (xxx-dbg) which you can manually install as needed.
To generate debug info for packages, you can add
local.conf. For example:
EXTRA_IMAGE_FEATURES = "debug-tweaks tools-profile dbg-pkgs"
Additionally, in order to generate the right type of debug info, we also need to
set PACKAGE_DEBUG_SPLIT_STYLE in the
PACKAGE_DEBUG_SPLIT_STYLE = 'debug-file-directory'