User Guide

Intel® VTune™ Profiler User Guide

ID 766319
Date 11/07/2023
Public
Document Table of Contents

Rebuild and Install Module i915 for GPU Analysis on Ubuntu*

To collect i915 ftrace events required to analyze the GPU utilization, your Linux kernel should be properly configured. If the Intel® VTune™ Profiler cannot start an analysis and provides an error message: Collection of GPU usage events cannot be enabled. i915 ftrace events are not available. You need to rebuild and install the re-configured module i915. For example, for kernel 4.14 and higher, these settings should be enabled: CONFIG_EXPERT=y and CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS=y.

If you update the kernel often, make sure to build the special kernel for GPU analysis.

On Ubuntu* systems, if you update the kernel rarely, you can configure and rebuild only module i915 as follows:

NOTE:

Installing the kernel requires root permissions.

  1. Add source package repositories for your Ubuntu* version.

    For example, on Ubuntu Bionic Beaver* add:

    sudo add-apt-repository -s "deb http://ru.archive.ubuntu.com/ubuntu/ bionic main restricted"

  2. Install build dependencies:

    sudo apt -y build-dep linux linux-image-$(uname -r)
    sudo apt -y install libncurses-dev flex bison openssl libssl-dev dkms libelf-dev libudev-dev libpci-dev libiberty-dev autoconf

  3. Install kernel headers:
    sudo apt -y install linux-headers-$(uname -r)
  4. Create a folder for kernel source:
    mkdir -p /tmp/kernel
    cd !$
  5. Download kernel sources:
    apt -y source linux
    cd linux-*
  6. Configure the kernel modules:
    cp /usr/src/linux-headers-$(uname -r)/.config ./
    cp /usr/src/linux-headers-$(uname -r)/Module.symvers ./
  7. Update the version in Makefile in the current directory.

    The version value should be the same as in the uname -r command output. For example, if uname -r prints 4.15.0-20-generic, the values in the Makefile must be:

    VERSION = 4

    PATCHLEVEL = 15

    SUBLEVEL = 0

    EXTRAVERSION = -20-generic

    Update the file, if required, and save it.

  8. Make sure the kernel version is set correctly in the Makefile:

    make kernelversion

    The command output for the example above must be:

    4.15.0-20-generic

  9. Update the new .config file, if required, and save it.

    Make sure the following settings in the file are enabled:

    CONFIG_EXPERT=y

    CONFIG_FTRACE=y

    CONFIG_DEBUG_FS=y

    CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS=y

  10. Create a full config file for the kernel:

    make olddefconfig

  11. Build module i915:

    make -j$(getconf _NPROCESSORS_ONLN) modules_prepare
    make -j$(getconf _NPROCESSORS_ONLN) M=./drivers/gpu/drm/i915 modules

    If you get the following error:

    LD [M] drivers/gpu/drm/i915/i915.o
    ld: no input files

    you need to replace the following lines in scripts/Makefile.build:

    link_multi_deps = \
    $(filter $(addprefix $(obj)/, \
    $($(subst $(obj)/,,$(@:.o=-objs))) \
    $($(subst $(obj)/,,$(@:.o=-y))) \
    $($(subst $(obj)/,,$(@:.o=-m)))), $^)

    with the line:

    link_multi_deps = $(filter %.o,$^)

  12. Install the new module:

    sudo make M=./drivers/gpu/drm/i915 modules_install

  13. Make sure the folder with the new driver is present in /etc/depmod.d/* files, or just add it:

    echo "search extradrivers" | sudo tee /etc/depmod.d/00-extra.conf

  14. Update initramfs:

    sudo depmod
    sudo update-initramfs -u

  15. Reboot the machine:

    sudo reboot

  16. Make sure the new driver is loaded:

    modinfo i915 | grep filename

    The expected command output is the following:

    filename: /lib/modules/4.15.0-20-generic/extradrivers/gpu/drm/i915/i915.ko

To roll back the changes and load the original module i915:

  1. Remove the folder with new driver from /etc/depmod.d/* files:

    sudo rm /etc/depmod.d/00-extra.conf

  2. Update initramfs:

    sudo depmod
    sudo update-initramfs -u

  3. Reboot the machine:

    sudo reboot