11.11 Profiling the Linux kernel
If you do not include the kernel in the images in the Capture & Analysis Options dialog box, the statistics generated by the kernel are not aligned with source code in the Analysis Reports. Before you can include the Linux kernel in the Program Images section of the Capture & Analysis Options dialog, you must build a version of vmlinux with kernel debug information enabled.
To profile the Linux kernel, follow these steps:
Enter the following command to enable you to change
In the Kernel Hacking
menu, select the Compile the kernel with debug
info option. This enables the
CONFIG_DEBUG_INFO kernel option.
Enter the following command to build the image:
make -j5 ARCH=arm
This creates a new vmlinux image.
NoteYou can profile a driver by either statically linking it into the kernel
image or by adding the module as an image in the Capture & Analysis Options dialog
Enable kernel stack unwinding using either of the following
Remove the comment tags that surround
GATOR_KERNEL_STACK_UNWINDING in the
Makefile and rebuild gator.ko.
Run the following command as root on the target after
gatord has started:
echo 1 >
This step is only required if you previously
built gator.ko with kernel
stack unwinding turned off.
Enabling kernel stack unwinding might trigger
errors that appear at millisecond intervals during the capture
session. If you experience this behavior, disable kernel stack
Open the Capture & Analysis
Options dialog box.
Click the Add ELF
image... button in the Program
Navigate to your vmlinux file and select it.
Start a new capture session.