[Bug 102199] New: Kabylake has poor performance with single display configurations

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=102199

            Bug ID: 102199
           Summary: Kabylake has poor performance with single display
                    configurations
           Product: DRI
           Version: unspecified
          Hardware: Other
                OS: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/Intel
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: lyude at redhat.com
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
                CC: intel-gfx-bugs at lists.freedesktop.org

Created attachment 133474
  --> https://bugs.freedesktop.org/attachment.cgi?id=133474&action=edit
dmidecode output

So, I've been trying to figure out why gnome-shell has been running slowly on
my laptop and unfortunately me and one of my coworkers have traced this down to
a rather interesting power issue: i915 doesn't upclock Kabylake GPUs quickly
enough to run gnome shell's animations smoothly, but only when running with a
single display. For instance, when continuously entering and exiting the
activities overlay according to /sys/kernel/debug/dri/0/i915_frequency_info,
the GPU almost never goes above 500MHz when running animations on a single
screen. The shell animations run at about 20FPS, and if I force the GPU's
frequency up using i915_min_freq animations begin running at 60 FPS again.
When running with two or more displays however, this problem never seems to
happen. The GPU upclocks as expected when shell animations start, and
everything runs fluidly at ~55-60 FPS.

The machine in question is a razer blade stealth running Fedora 26. The display
being used in the single monitor configuration is the built-in eDP 4K display.
I've tried the latest 4.13 rc4 kernel, and unfortunately the performance isn't
much better.

I've attached my dmidecode, and will reboot and attach a dmesg with
drm.debug=0x6 in just a moment. let me know if you need any more information.

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are on the CC list for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20170813/130fe5b5/attachment.html>