User Guide

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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:
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

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.