Intel: less productivity and more heat with --experimental-backends

Platform

Arch Linux (linux kernel)

GPU, drivers, and screen setup

Intel Iris Pro 5200 Modesetting kernel driver, no xf86-video-intel installed.

/etc/modprobe.d/i915.conf:

options i915 modeset=1 enable_fbc=0 fastboot=1 disable_power_well=1 mitigations=off

Internal screen: 2k 2880x1800, external 2k 2560x1440

Environment

i3-gaps

picom version

**Version:** vgit-ee7d9
### Extensions:
* Shape: Yes
* XRandR: Yes
* Present: Present
### Misc:
* Use Overlay: No (Another compositor is already running)
* Config file used: /home/tarkh/.config/picom/picom.conf
### Drivers (inaccurate):
Intel
### Backend: glx
* Driver vendors:
* GLX: Mesa Project and SGI
* GL: Intel Open Source Technology Center
* GL renderer: Mesa DRI Intel(R) Iris(R) Pro Graphics P5200 (HSW GT3)
* Accelerated: 1

Configuration:

#################################
#             Shadows           #
#################################

# Enabled client-side shadows on windows. Note desktop windows
# (windows with '_NET_WM_WINDOW_TYPE_DESKTOP') never get shadow,
# unless explicitly requested using the wintypes option.
#
# shadow = false
shadow = true;

# The blur radius for shadows, in pixels. (defaults to 12)
# shadow-radius = 12
shadow-radius = 7;

# The opacity of shadows. (0.0 - 1.0, defaults to 0.75)
# shadow-opacity = .75

# The left offset for shadows, in pixels. (defaults to -15)
# shadow-offset-x = -15
shadow-offset-x = -7;

# The top offset for shadows, in pixels. (defaults to -15)
# shadow-offset-y = -15
shadow-offset-y = -7;

# Red color value of shadow (0.0 - 1.0, defaults to 0).
# shadow-red = 0

# Green color value of shadow (0.0 - 1.0, defaults to 0).
# shadow-green = 0

# Blue color value of shadow (0.0 - 1.0, defaults to 0).
# shadow-blue = 0

# Hex string color value of shadow (#000000 - #FFFFFF, defaults to #000000). This option will override options set shadow-(red/green/blue)
# shadow-color = "#000000"

# Specify a list of conditions of windows that should have no shadow.
#
# examples:
#   shadow-exclude = "n:e:Notification";
#
# shadow-exclude = []
shadow-exclude = [
  "class_g ~= 'firefox' && window_type *= 'utility'",
  "name = 'Notification'",
  "class_g = 'Conky'",
  "class_g ?= 'Notify-osd'",
  "class_g = 'Cairo-clock'",
  "_GTK_FRAME_EXTENTS@:c"
];

# Specify a list of conditions of windows that should have no shadow painted over, such as a dock window.
# clip-shadow-above = []

# Specify a X geometry that describes the region in which shadow should not
# be painted in, such as a dock window region. Use
#    shadow-exclude-reg = "x10+0+0"
# for example, if the 10 pixels on the bottom of the screen should not have shadows painted on.
#
# shadow-exclude-reg = ""

# Crop shadow of a window fully on a particular Xinerama screen to the screen.
# xinerama-shadow-crop = false

#################################
#           Fading              #
#################################

# Fade windows in/out when opening/closing and when opacity changes,
#  unless no-fading-openclose is used.
# fading = false
fading = true;

# Opacity change between steps while fading in. (0.01 - 1.0, defaults to 0.028)
# fade-in-step = 0.028
fade-in-step = 0.03;

# Opacity change between steps while fading out. (0.01 - 1.0, defaults to 0.03)
# fade-out-step = 0.03
fade-out-step = 0.03;

# The time between steps in fade step, in milliseconds. (> 0, defaults to 10)
# fade-delta = 10

# Specify a list of conditions of windows that should not be faded.
# fade-exclude = []

# Do not fade on window open/close.
# no-fading-openclose = false

# Do not fade destroyed ARGB windows with WM frame. Workaround of bugs in Openbox, Fluxbox, etc.
# no-fading-destroyed-argb = false

#################################
#   Transparency / Opacity      #
#################################

# Opacity of inactive windows. (0.1 - 1.0, defaults to 1.0)
# inactive-opacity = 1
inactive-opacity = 0.8;

# Opacity of window titlebars and borders. (0.1 - 1.0, disabled by default)
# frame-opacity = 1.0
frame-opacity = 0.7;

# Let inactive opacity set by -i override the '_NET_WM_OPACITY' values of windows.
# inactive-opacity-override = true
inactive-opacity-override = false;

# Default opacity for active windows. (0.0 - 1.0, defaults to 1.0)
# active-opacity = 1.0

# Dim inactive windows. (0.0 - 1.0, defaults to 0.0)
# inactive-dim = 0.0

# Specify a list of conditions of windows that should never be considered focused.
# focus-exclude = []
focus-exclude = [ "class_g = 'Cairo-clock'" ];

# Use fixed inactive dim value, instead of adjusting according to window opacity.
# inactive-dim-fixed = 1.0

# Specify a list of opacity rules, in the format `PERCENT:PATTERN`,
# like `50:name *= "Firefox"`. picom-trans is recommended over this.
# Note we don't make any guarantee about possible conflicts with other
# programs that set '_NET_WM_WINDOW_OPACITY' on frame or client windows.
# example:
#    opacity-rule = [ "80:class_g = 'URxvt'" ];
#
# opacity-rule = []

#################################
#           Corners             #
#################################

# Sets the radius of rounded window corners. When > 0, the compositor will
# round the corners of windows. Does not interact well with
# `transparent-clipping`.
corner-radius = 0

# Exclude conditions for rounded corners.
rounded-corners-exclude = [
  "window_type = 'dock'",
  "window_type = 'desktop'"
];

#################################
#     Background-Blurring       #
#################################

# Parameters for background blurring, see the *BLUR* section for more information.
# blur-method =
blur-method = "dual_kawase"
# blur-size = 12
#
# blur-deviation = false
#
# blur-strength = 5
blur-strength = 4

# Blur background of semi-transparent / ARGB windows.
# Bad in performance, with driver-dependent behavior.
# The name of the switch may change without prior notifications.
#
# blur-background = false
#blur-background =  true
# Blur background of windows when the window frame is not opaque.
# Implies:
#    blur-background
# Bad in performance, with driver-dependent behavior. The name may change.
#
# blur-background-frame = false

# Use fixed blur strength rather than adjusting according to window opacity.
# blur-background-fixed = false

# Specify the blur convolution kernel, with the following format:
# example:
#   blur-kern = "5,5,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1";
#
# blur-kern = ""
#blur-kern = "3x3box";

# Exclude conditions for background blur.
# blur-background-exclude = []
blur-background-exclude = [
  "class_g ~= 'firefox' && window_type *= 'utility'",
  #"window_type = 'dock'",
  "window_type = 'desktop'",
  "_GTK_FRAME_EXTENTS@:c"
];

#################################
#       General Settings        #
#################################

# Daemonize process. Fork to background after initialization. Causes issues with certain (badly-written) drivers.
# daemon = false

# Specify the backend to use: `xrender`, `glx`, or `xr_glx_hybrid`.
# `xrender` is the default one.
#
# backend = "glx"
backend = "glx";
# Enable/disable VSync.
# vsync = false
vsync = true;

# Enable remote control via D-Bus. See the *D-BUS API* section below for more details.
# dbus = false

# Try to detect WM windows (a non-override-redirect window with no
# child that has 'WM_STATE') and mark them as active.
#
# mark-wmwin-focused = false
mark-wmwin-focused = true;

# Mark override-redirect windows that doesn't have a child window with 'WM_STATE' focused.
# mark-ovredir-focused = false
mark-ovredir-focused = true;

# Try to detect windows with rounded corners and don't consider them
# shaped windows. The accuracy is not very high, unfortunately.
#
# detect-rounded-corners = false
detect-rounded-corners = true;

# Detect '_NET_WM_OPACITY' on client windows, useful for window managers
# not passing '_NET_WM_OPACITY' of client windows to frame windows.
#
# detect-client-opacity = false
detect-client-opacity = true;

# Specify refresh rate of the screen. If not specified or 0, picom will
# try detecting this with X RandR extension.
#
# refresh-rate = 60
refresh-rate = 0;

# Use EWMH '_NET_ACTIVE_WINDOW' to determine currently focused window,
# rather than listening to 'FocusIn'/'FocusOut' event. Might have more accuracy,
# provided that the WM supports it.
#
# use-ewmh-active-win = false

# Unredirect all windows if a full-screen opaque window is detected,
# to maximize performance for full-screen windows. Known to cause flickering
# when redirecting/unredirecting windows.
#
# unredir-if-possible = false
unredir-if-possible = true
# Delay before unredirecting the window, in milliseconds. Defaults to 0.
# unredir-if-possible-delay = 0
unredir-if-possible-delay = 500
# Conditions of windows that shouldn't be considered full-screen for unredirecting screen.
# unredir-if-possible-exclude = []

# Use 'WM_TRANSIENT_FOR' to group windows, and consider windows
# in the same group focused at the same time.
#
# detect-transient = false
detect-transient = true;

# Use 'WM_CLIENT_LEADER' to group windows, and consider windows in the same
# group focused at the same time. 'WM_TRANSIENT_FOR' has higher priority if
# detect-transient is enabled, too.
#
# detect-client-leader = false
detect-client-leader = true;

# Resize damaged region by a specific number of pixels.
# A positive value enlarges it while a negative one shrinks it.
# If the value is positive, those additional pixels will not be actually painted
# to screen, only used in blur calculation, and such. (Due to technical limitations,
# with use-damage, those pixels will still be incorrectly painted to screen.)
# Primarily used to fix the line corruption issues of blur,
# in which case you should use the blur radius value here
# (e.g. with a 3x3 kernel, you should use `--resize-damage 1`,
# with a 5x5 one you use `--resize-damage 2`, and so on).
# May or may not work with *--glx-no-stencil*. Shrinking doesn't function correctly.
#
# resize-damage = 1

# Specify a list of conditions of windows that should be painted with inverted color.
# Resource-hogging, and is not well tested.
#
# invert-color-include = []

# GLX backend: Avoid using stencil buffer, useful if you don't have a stencil buffer.
# Might cause incorrect opacity when rendering transparent content (but never
# practically happened) and may not work with blur-background.
# My tests show a 15% performance boost. Recommended.
#
# glx-no-stencil = false
glx-no-stencil =  true
# GLX backend: Avoid rebinding pixmap on window damage.
# Probably could improve performance on rapid window content changes,
# but is known to break things on some drivers (LLVMpipe, xf86-video-intel, etc.).
# Recommended if it works.
#
# glx-no-rebind-pixmap = false
glx-no-rebind-pixmap = true

# Disable the use of damage information.
# This cause the whole screen to be redrawn everytime, instead of the part of the screen
# has actually changed. Potentially degrades the performance, but might fix some artifacts.
# The opposing option is use-damage
#
# no-use-damage = false
use-damage = true;

# Use X Sync fence to sync clients' draw calls, to make sure all draw
# calls are finished before picom starts drawing. Needed on nvidia-drivers
# with GLX backend for some users.
#
# xrender-sync-fence = false
#xrender-sync-fence =  true

# GLX backend: Use specified GLSL fragment shader for rendering window contents.
# See `compton-default-fshader-win.glsl` and `compton-fake-transparency-fshader-win.glsl`
# in the source tree for examples.
#
# glx-fshader-win = ""
#glx-fshader-win = "compton-fake-transparency-fshader-win.glsl"
# Force all windows to be painted with blending. Useful if you
# have a glx-fshader-win that could turn opaque pixels transparent.
#
# force-win-blend = false
#force-win-blend =  true
# Do not use EWMH to detect fullscreen windows.
# Reverts to checking if a window is fullscreen based only on its size and coordinates.
#
# no-ewmh-fullscreen = false

# Dimming bright windows so their brightness doesn't exceed this set value.
# Brightness of a window is estimated by averaging all pixels in the window,
# so this could comes with a performance hit.
# Setting this to 1.0 disables this behaviour. Requires --use-damage to be disabled. (default: 1.0)
#
# max-brightness = 1.0

# Make transparent windows clip other windows like non-transparent windows do,
# instead of blending on top of them.
#
# transparent-clipping = false

# Set the log level. Possible values are:
#  "trace", "debug", "info", "warn", "error"
# in increasing level of importance. Case doesn't matter.
# If using the "TRACE" log level, it's better to log into a file
# using *--log-file*, since it can generate a huge stream of logs.
#
# log-level = "debug"
log-level = "warn";

# Set the log file.
# If *--log-file* is never specified, logs will be written to stderr.
# Otherwise, logs will to written to the given file, though some of the early
# logs might still be written to the stderr.
# When setting this option from the config file, it is recommended to use an absolute path.
#
log-file = "/tmp/picom.log"

# Show all X errors (for debugging)
# show-all-xerrors = false

# Write process ID to a file.
# write-pid-path = "/path/to/your/log/file"

# Window type settings
#
# 'WINDOW_TYPE' is one of the 15 window types defined in EWMH standard:
#     "unknown", "desktop", "dock", "toolbar", "menu", "utility",
#     "splash", "dialog", "normal", "dropdown_menu", "popup_menu",
#     "tooltip", "notification", "combo", and "dnd".
#
# Following per window-type options are available: ::
#
#   fade, shadow:::
#     Controls window-type-specific shadow and fade settings.
#
#   opacity:::
#     Controls default opacity of the window type.
#
#   focus:::
#     Controls whether the window of this type is to be always considered focused.
#     (By default, all window types except "normal" and "dialog" has this on.)
#
#   full-shadow:::
#     Controls whether shadow is drawn under the parts of the window that you
#     normally won't be able to see. Useful when the window has parts of it
#     transparent, and you want shadows in those areas.
#
#   clip-shadow-above:::
#     Controls wether shadows that would have been drawn above the window should
#     be clipped. Useful for dock windows that should have no shadow painted on top.
#
#   redir-ignore:::
#     Controls whether this type of windows should cause screen to become
#     redirected again after been unredirected. If you have unredir-if-possible
#     set, and doesn't want certain window to cause unnecessary screen redirection,
#     you can set this to `true`.
#
wintypes:
{
  tooltip = { fade = true; shadow = true; opacity = 0.75; focus = true; full-shadow = false; };
  dock = { fade = true; shadow = false; clip-shadow-above = true; }
  dnd = { shadow = false; }
  popup_menu = { opacity = 0.8; }
  dropdown_menu = { opacity = 0.8; }
};

Steps of reproduction

If I run setup without --experimental-backends, I've got more Blitter/Video utilization in intel-gpu-top app, which results in less heat dissipation (at least 10-15 C).

Watching YouTube video (Firefox with hardware accel + h264ify): Without --experimental-backends:

Render/3D: ~ 60-75%
Blitter/Video: ~ 20-35%

With --experimental-backends

Render/3D: ~ 60-75%
Blitter/Video: ~ 7-10%

LIBGL_DEBUG=verbose DRI_PRIME=1 vblank_mode=0 glxgears Without --experimental-backends

libGL: using driver i915 for 4
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/tarkh/.drirc: No such file or directory.
libGL: pci id for fd 4: 8086:0d26, driver i965
libGL: MESA-LOADER: dlopen(/usr/lib/dri/i965_dri.so)
ATTENTION: default value of option vblank_mode overridden by environment.
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/tarkh/.drirc: No such file or directory.
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/tarkh/.drirc: No such file or directory.
libGL: Using DRI3 for screen 0
8645 frames in 5.0 seconds = 1728.884 FPS
8619 frames in 5.0 seconds = 1723.641 FPS
8967 frames in 5.0 seconds = 1793.258 FPS
9073 frames in 5.0 seconds = 1814.425 FPS
9050 frames in 5.0 seconds = 1809.958 FPS

With --experimental-backends

libGL: using driver i915 for 4
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/tarkh/.drirc: No such file or directory.
libGL: pci id for fd 4: 8086:0d26, driver i965
libGL: MESA-LOADER: dlopen(/usr/lib/dri/i965_dri.so)
ATTENTION: default value of option vblank_mode overridden by environment.
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/tarkh/.drirc: No such file or directory.
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/tarkh/.drirc: No such file or directory.
libGL: Using DRI3 for screen 0
7325 frames in 5.0 seconds = 1464.982 FPS
7571 frames in 5.0 seconds = 1514.165 FPS
7520 frames in 5.0 seconds = 1503.929 FPS
7602 frames in 5.0 seconds = 1520.257 FPS
7339 frames in 5.0 seconds = 1467.797 FPS

Expected behavior

It works pretty well with old backends, watching 1060p60 videos keeps playing smoothly and temps stays below 65-70 C.

Current Behavior

Recently I tried to set up dual_kawase background blur, so I enabled experimental backends and got above results. While same videos still plays smoothly, my average temps rises to 80-85 C, which makes fans work louder. ** Same result with dual_kawase blur disabled.

Other details

I've tried to run setup with xf86-video-intel installed, tried Option "AccelMethod": sna, uxa, blt - didn't get any noticeable difference. Also tried to use only internal display, tweaking Option "TearFree" "true" and Option "DRI" "3" - same nothing. Option "DRI" "2" makes situation worse.

Any thoughts? Where to dig? Thank you!

yshui / picom