dual GPU issue

[ltwally]

I recently upgraded my computer to a dual-GPU / triple-monitor configuration running Vista x64. I've been noticing that dwm.exe chews quite a bit more CPU time (~10-30% - the larger the video window the more CPU time it chews) when watching video with VLC on a monitor attached to my secondary graphics card. When watching video with VLC on a monitor attached to my primary graphics card, dwm.exe is completely idle.

If you think about it, even just 10% on a quad-core 2.66ghz CPU is an awful lot. And this doesn't happen when I move VLC to a monitor attached to my primary GPU.

I mainly use my 16:9 23" monitor for watching movies, and would like to be able to keep it attached to the secondary GPU if possible.


Below are my system details, as would pertain to video playback. If you need anything further just ask.

• motherboard: MSI P6N Diamond (nVidia nForce 680i / 430i chipsets)
• cpu: Intel Q6700 Core2Quad (2.66ghz)
• memory: 4 x 2gig (8gigs)
• gpu: dual nVidia GeForce GTS 250 (1gig memory each) w/ SLI link attached
• monitors: 2 Samsung 226BW (attached to primary GPU), 1 Samsung 2343BWX (attached to secondary GPU)
• screen resolution: (1) 1680x1050, (2) 1680x1050, (3) 2048x1152
• operating system: Windows Vista x64 w/ SP1
• vlc: version 0.9.9 and 1.0.0-rc1
• nvidia drivers: GeForce 185.85, nForce 15.25
• Aero is enabled.
• SLI is disabled while watching movies.
• PhysX is disabled while watching movies.
• Nothing is over-clocked.
• VLC's video is set to "DirectX 3D" video output. (I have also tried "default" & "DirectX" for output.)

This issue with dwm.exe doesn't crop up when I use other software to watch movies on that third monitor, such as Media Player Classic and Windows Media Player.

I'm hoping someone out there knows of a configuration change I can make in VLC to improve this situation. Thanks!

[ltwally]

I have been testing the different video output modules, and have found that "windows GDI output" has significantly reduced CPU usage... but video quality takes a hit.

Still hoping someone knows of another solution. Thanks!

[VLC_help]

Video output module is only thing that should matter (and Overlay, but it isn't the issue in this case).

[ltwally]

As stated above, this issue clears up if I use the "Windows GDI" output, this problem clears up. Unfortunately, the picture quality of that output module is grainy.

[ltwally]

This problem is irritating as hell. I've tried every single output module, disabling/enabling overlay, hardware YUV, the various CPU features, etc etc. Nothing I do seems to cure it. (Excepting for using the "Windows GDI" output module. But that's hardly a solution - the quality on that module is poopy.)

Watching a full-screen video in Media Player Classic Home Cinema uses 1-2% CPU time for it (mplayerc.exe), and 1-2% CPU for dwm.exe.

That same video in VLC 1.0.0-rc1 uses 1-2% CPU time for VLC, and 12-14% CPU time for dwm.exe. As well, the video is jerky and it slows down all graphics on the system. (Other applications graphics are slowed as well. Such as the movement of cards in a game of solitare, or typing things in a browser.) If I move VLC to a monitor attached to my primary GPU dwm.exe settles down to 1-2% CPU usage.

Any developers or experts out there that might have an idea what the problem is, and if there is anything that can be done to fix it?

Thanks again.

[VLC_help]

It must be issue with Desktop Window Manager that for some reason doesn't handle seconds screen buffers correctly when certain drawing methods are used. MPC Home Cinema and VLC use different video outputs, and that is why it doesn't work same on both programs (VLC cannot do VMR or EVR).

If there is some API call in Desktop Window Manager that could be used to prevent thumbnailing (or what ever is spiking the CPU) then the issue could be fixed. But first we have to know what part of DWM causes the high CPU usage.

[ltwally]

I'd be willing to help test if anyone wanted me to.

Till then, I suppose the best I can do is put in a bug report... or, maybe not...

The bugtracker (https://trac.videolan.org/vlc/) gives me this when I try to load it:

Code: Select all

Traceback (most recent call last): File "/usr/lib/python2.5/site-packages/trac/web/api.py", line 339, in send_error 'text/html') File "/usr/lib/python2.5/site-packages/trac/web/chrome.py", line 684, in render_template data = self.populate_data(req, data) File "/usr/lib/python2.5/site-packages/trac/web/chrome.py", line 592, in populate_data d['chrome'].update(req.chrome) File "/usr/lib/python2.5/site-packages/trac/web/api.py", line 169, in __getattr__ value = self.callbacks[name](self) File "/usr/lib/python2.5/site-packages/trac/web/chrome.py", line 460, in prepare_request for category, name, text in contributor.get_navigation_items(req): File "/usr/lib/python2.5/site-packages/trac/versioncontrol/web_ui/browser.py", line 295, in get_navigation_items if 'BROWSER_VIEW' in req.perm: File "/usr/lib/python2.5/site-packages/trac/perm.py", line 523, in has_permission return self._has_permission(action, resource) File "/usr/lib/python2.5/site-packages/trac/perm.py", line 537, in _has_permission check_permission(action, perm.username, resource, perm) File "/usr/lib/python2.5/site-packages/trac/perm.py", line 424, in check_permission perm) File "/usr/lib/python2.5/site-packages/trac/perm.py", line 282, in check_permission get_user_permissions(username) File "/usr/lib/python2.5/site-packages/trac/perm.py", line 357, in get_user_permissions for perm in self.store.get_user_permissions(username): File "/usr/lib/python2.5/site-packages/trac/perm.py", line 175, in get_user_permissions cursor.execute("SELECT username,action FROM permission") File "/usr/lib/python2.5/site-packages/trac/db/util.py", line 51, in execute return self.cursor.execute(sql) File "/usr/lib/python2.5/site-packages/trac/db/util.py", line 51, in execute return self.cursor.execute(sql) OperationalError: FATAL: terminating connection due to administrator command server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request.

VLC truely hates me of late

[VLC_help]

trac hates everyone equally =)

[ltwally]

Well, in the mean time, I'm forced to use MPC & WMP to watch videos. It's not a huge problem, but I'd really love it if we could get VLC working properly on a Vista dual-GPU/triple-monitor configuration. I'd be more than willing to help test new builds or configuration settings, if anyone wanted to look into it.

[ltwally]

Upgraded to 1.0 "gold" and still having this issue.

Anyone else with a multi-GPU / multi-monitor setup having this problem?

[High-Voltage]

Right now, two years later and using Win7 still the same problem
My second graphics card is less powerfull than the primairy is, so I thought that was the problem. I was nearly heading for the shop to buy a better one.
But it seems the problem is invoked by VLC rather than the hardware config.

Oh well, I will try Media Player Classic.


Sorry for kicking this thread up

[eD_Nort]

My current setup only has a single video card with dual monitors and I was having dwm lag issue regardless of which monitor I was viewing on. To stop my entire system from being eaten alive by dwm, I right clicked on vlc.exe and selected properties, and then on the Compatibility tab I checked "Disable desktop composition". As far as actual video lag, I used a trick I used for high def videos on my old XP machine, which is to set the video->deinterlace mode to discard. Neither of these are ideal solutions, since the video is still dropping frames, and the compatibility mode is intrusive. Would be ideal if there was a way to disable the dwm features/overhead from within vlc.