Bug 93971

Summary:

video framerate performance regression with UXA

Product:

DRI

Reporter:

Kevin Mitchell <kevmitch>

Component:

DRM/Intel

Assignee:

Intel GFX Bugs mailing list <intel-gfx-bugs>

Status:

CLOSED WORKSFORME

QA Contact:

Intel GFX Bugs mailing list <intel-gfx-bugs>

Severity:

normal

Priority:

medium

CC:

intel-gfx-bugs, kevmitch

Version:

XOrg git

Keywords:

bisected, regression

Hardware:

Other

OS:

All

Whiteboard:

i915 platform:

IVB

i915 features:

Attachments:

Description	Flags
Xorg.0.log at 6db906ea8188cd7f731e5ef7391115ee8f5c17c8,	none
dmesg with drm.debug=0x06	none

Description Kevin Mitchell 2016-02-02 20:11:02 UTC

Created attachment 121469 [details]
Xorg.0.log at 6db906ea8188cd7f731e5ef7391115ee8f5c17c8,

With UXA on my Lenovo Thinkpad T530 Ivy Bridge machine, playing video with mpv (https://github.com/mpv-player/mpv) worked fine keeping up with my 60hz LVDS or HDMI TV using the command

    mpv file.mkv --no-config --fs --vo=opengl:scale=spline36 --video-sync=display-vdrop --osd-msg1='${estimated-display-fps}' 

This is the bare minimum opengl output driver with a mid-quality spline36 luma scaler implemented as an opengl shader. The added "--video-sync=display-vdrop --osd-msg1='${estimated-display-fps}' " activates display sync and displays the effective framerate on the screen.

At d909c460743a0cabc5c0ed30e063e99af7b26b17, it seems that vsyncs start to happen about twice as fast ~120fps on the 60hz displays. Then, three commits later at 6db906ea8188cd7f731e5ef7391115ee8f5c17c8, it appears that I am no longer able to render frames fast enough for the refresh rate so that it bounces around 50 +/- 5 fps on either display. The problem goes away if I remove the scale=spline36 scaler so that it falls back to cheaper bilinear, which is why I say this is a performance regression.  Similarly, the hardly taxing GLXgears appears to render ~60fps just fine.

The problem also does not appear to exist for SNA, but I am unable to use that mode due to other problems (#91066).

Comment 1 Kevin Mitchell 2016-02-02 20:12:24 UTC

Created attachment 121470 [details]
dmesg with drm.debug=0x06

mpv is playing stuttery video between 18.237840 and 21.528853

Comment 2 Kevin Mitchell 2016-02-02 20:12:51 UTC

I should add that I am using Linux 4.4.0

Comment 3 Kevin Mitchell 2016-12-11 10:47:38 UTC

This no longer seems to be a problem using with Driver "intel" to load the debian packaged xserver-xorg-video-intel=2.99.917+git20161105-1+b1. (linux-4.10, mpv git-b60817f9dd).

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