Skip to content

Instantly share code, notes, and snippets.

@BlackDex

BlackDex/skylake-tuning-linux.md

Forked from Brainiarc7/skylake-tuning-linux.md
Last active May 2, 2020 03:29
Show Gist options
  • Save BlackDex/4962fd0f30eae2b8ef1650e28df77720 to your computer and use it in GitHub Desktop.
Save BlackDex/4962fd0f30eae2b8ef1650e28df77720 to your computer and use it in GitHub Desktop.
Download ZIP
This gist will show you how to tune your Intel-based Skylake, Kabylake and beyond Integrated Graphics Core for performance and reliability through GuC and HuC firmware usage on Linux.
Raw
skylake-tuning-linux.md

Tuning Intel Skylake and beyond for optimal performance and feature level support on Linux:

Note that on Skylake, Kabylake (and the now cancelled "Broxton") SKUs, functionality such as power saving, GPU scheduling and HDMI audio have been moved onto binary-only firmware, and as such, the GuC and the HuC blobs must be loaded at run-time to access this functionality.

Enabling GuC and HuC on Skylake and above requires a few extra parameters be passed to the kernel before boot.

Instructions provided for both Fedora and Ubuntu (including Debian):

Note that the firmware for these GPUs is often packaged by your distributor, and as such, you can confirm the firmware blob's availability by running:

1. On Fedora:

rpm -ql linux-firmware | fgrep i915

Sample output:

/usr/lib/firmware/i915 
/usr/lib/firmware/i915/bxt_dmc_ver1_07.bin 
/usr/lib/firmware/i915/kbl_dmc_ver1.bin
/usr/lib/firmware/i915/kbl_dmc_ver1_01.bin 
/usr/lib/firmware/i915/skl_dmc_ver1_23.bin 
/usr/lib/firmware/i915/skl_guc_ver1.bin 
/usr/lib/firmware/i915/skl_guc_ver4.bin 
/usr/lib/firmware/i915/skl_guc_ver6.bin 
/usr/lib/firmware/i915/skl_guc_ver6_1.bin 
/usr/share/doc/linux-firmware/LICENSE.i915

2. On Ubuntu:

dpkg -L linux-firmware | fgrep i915

It may be wise to install the linux-firmware-nonfree package as it may contain extra firmware blobs on Ubuntu releases prior to 16.04LTS. Don't install this on 16.04LTS and above.

Now, to the real meat:

GUC loading on Skylake and above:

Add this to the kernel boot parameters on /etc/default/grub:

intel_pstate=skylake_hwp

The intel_pstate=skylake_hwp option enables Intel's Hardware P-States, known commonly by the marketing moniker "SpeedShift". Note that Intel's IOMMU for VT-d (enabled in the kernel by passing intel_iommu=on to the kernel boot options) cannot be used together with frame buffer compression (i915.enable_fbc=1 argument passed to the i915). Frame Buffer Compression will be disabled automatically to prevent screen tearing in this case.

Note: The intel_pstate driver is the default since Linux 4.10 on SKL+. Thanks for the updates on this @pcordes and the correction on module options syntax in /etc/modprobe.d/i915.conf, @vinzent. Gr33ts ;-)

Then, update grub on Fedora:

(Run commands as root):

For EFI boot (More common):

grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg

And if you're still booting up in legacy BIOS mode on an MBR-style partitioning scheme or with CSM enabled on Fedora for whatever reason:

grub2-mkconfig -o /boot/grub2/grub.cfg

Then rebuild initramfs:

On Fedora:

dracut --force

On Debian-based distributions:

Simply run:

sudo update-initramfs

update-grub

Then reboot.

Your modern Intel HD Graphics processor graphics will work just fine.

You can also add this to: /etc/modprobe.d/i915.conf

In the following syntax:

options i915 enable_guc=3

Other safe options to pass are enable_rc6=1, enable_fbc=1, enable_psr=1, disable_power_well=0 and semaphores=1

Reference:

See modinfo output for i915 for available GuC options:

modinfo i915 | grep guc

Further notes:

A list of all options along with short descriptions and default values can be generated with the following command:

$ modinfo -p i915

To check which options are currently enabled, run:

# systool -m i915 -av

You will note that many options default to -1, resulting in per-chip power-saving defaults. It is however possible to configure more aggressive powersaving by using module options. Warning: Diverting from the defaults will mark the kernel as tainted from Linux 3.18 onwards. This basically implies using other options than the per-chip defaults is considered experimental and not supported by the developers.

The following set of options should be generally safe to enable:

/etc/modprobe.d/i915.conf

options i915 enable_dc=1 enable_fbc=1 semaphores=1 enable_guc=3

On Linux 4.16+, GuC firmware loading and submission is now handled by the enable_guc parameter in place of the former enable_guc_loading=1 and enable_guc_submission=1 parameters. Adjust as needed.

RC6 sleep modes (enable_rc6):

You can experiment with higher values for enable_rc6, but your GPU may not support them or the activation of the other options:

The available enable_dc values are a bitmask with bit values RC6=1, RC6p=2, RC6pp=4[4] - where "RC6p" and "RC6pp" are lower power states.

To confirm the current running RC6 level, you can look in sysfs:

# cat /sys/class/drm/card0/power/rc6_enable

If the value read is a lower number than expected, the other RC6 level are probably not supported. Passing drm.debug=0xe to the kernel boot options will add DRM debugging information to the kernel log - possibly including a line like this:

[drm:sanitize_rc6_option] Adjusting RC6 mask to 1 (requested 7, valid 1)

Framebuffer compression (enable_fbc):

Framebuffer compression may be unreliable or unavailable on Intel GPU generations before Sandy Bridge (generation 6). This results in messages logged to the system journal similar to this one:

kernel: drm: not enough stolen space for compressed buffer, disabling.

Tear-free video:

With the SNA acceleration method enabled, tearing may be observed. To fix this, enable the "TearFree" option in the driver by adding the following line to your xorg.conf (or ideally, a sub-configuration file under xorg.conf.d) configuration file:

Option "TearFree" "true"

This is not needed on server-grade SKUs where Xorg is unwelcome.

Debugging:

Simply inspect dmesg:

dmesg | grep drm

And also look at the output of:

journalctl -b -o short-monotonic -k

Screen corruption observed when waking up from suspend

This is often observed as font and screen corruption in GTK+ applications (missing glyphs after suspend/resume).

Should you experience missing font glyphs in GTK+ applications, the following workaround might help. Edit /etc/environment to add the following line:

/etc/environment
COGL_ATLAS_DEFAULT_BLIT_MODE=framebuffer

See this bug here for more details.

Thanks and regards,

Brainiarc7

Some Extra Stuff cat /sys/kernel/debug/dri/0/i915_guc_load_status

/usr/share/X11/xorg.conf.d/20-intel.conf

Section "Device"
    Identifier  "Intel Graphics"
    Driver      "intel"
    Option      "AccelMethod" "sna"
    Option      "TearFree" "true"
    Option      "DRI" "3"
EndSection

Section "Device"
  Identifier  "Intel Graphics"
  Driver      "intel"
  Option      "TripleBuffer" "true"
  Option      "TearFree"     "true"
EndSection

https://hobo.house/2018/05/18/fix-for-intel-i915-gpu-freeze-on-recent-linux-kernels/

cat > /etc/X11/xorg.conf.d/10-intel.conf <<EOF
Section "Device"
Identifier "Intel Graphics"
Driver "intel"
EndSection
EOF

https://wiki.archlinux.org/index.php/intel_graphics

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment