Windows vs. Linux On 3D Performance

Linux Games have posted this article about Windows VS Linux on 3D performace. They tested Quake III with Matrox G400, NVidia GeForce 256 DDR, and 3DFX Voodoo 3 3000 -- all with their latest drivers (both Linux drivers and Windows drivers). There are some interesting results, and even a few surprises. What do you think about the results?

Comments

Windows is not even involved here.

[be-fan]

I am surprised that this became a Linux vs Windows kind of thing. Windows is not even involved in this story. When a game developer writes on Windows, he would be stupid to use any more of Win32 than needed to create the window and delete the window. Most Windows games today are programmed in DirectX, which offers almost all the services needed by a game. Once one learns how to set up a windows and do some threads, almost everything else a game needs is done through calls to DirectX instead of OS calls. In addition to that, most games spend most of their time inside their own code anyway, so the OS has a negligible effect on performance, (assuming of course that the app has direct or near direct access to hardware). Som in reality the competition is Linux vs. DirectX. Quite an impressive showing on Linux's part, at least for now. DirectX (true to its name) has much less overhead that any OS ever could. I wonder, however, if this success is short-lived. Quake isn't exactly a service intensive game. Sound is pretty basic, as is input. They only thing that really matters in this case is the speed of 3D subsystem. Game, however, will eventually evolve, in particular using more sound. Some games (thief in particular) already do this. I really wonder if Linux can handle yet another subsystem that needs direct access to hardware. As 3D sound controllers become more complex (like Aureal's controllers) the OS will need a good way to get huge amounts of data and commands to the sound cards. In these types of games, Windows will keep trumping Linux. The main problem is that Linux doesn't have DirectX. In absense of that, it has no consistant API that pushes the OS out of the way and allows the game to take over the system. Take a look at the rest of the APIs. DirectSound, DirectInput, DirectDraw, and to some extent DirectPlay (for its flexibility) whoops anything availible on Linux. (Any Linux driver-hardware combo that allows 32 HW accelerated 3D sound streams in addition to 96 normal streams? Windows had that in the A3D 2.0 days.) What Linux really needs at this point is a DRI for the rest of the sub systems. Only then, will Linux become better than Windows for games. Some will say the current situation is enough. Linux is almost as good as windows, it performs almost as well. Almost will not cause anybody to switch, however. If Linux really is a technically superior system, it should be able to trounce windows, not merely equal it.

Wrong

[roystgnr]

It's all X's fault. That said, having a networked client/server GUI beats the shit out of a single-user, single desktop GUI anytime.

It's a shame you can't mod and post in the same story; I'd like to be able to both negate the "insightful" rating and explain why it's BS.

Take a look at the drivers they used. Not a one of them sends data over the X pipe. The X server basically is there to say, "yeah, you can bang directly on the hardware" and then get out of the way.

If they were sending data over the X pipe, you'd definitely know it. 3D hardware acceleration is often bandwidth limited; you could get up to a 50% drop in framerate without direct rendering. Smart design would reduce this problem, but I still suspect you'd see 70% optimal framerate, max... and in the LinuxGames tests, 70% was the worst case, not the best.

What was the best case? 99% framerate. This suggests to me that it's not idle processes or the kernel hogging CPU, it's not any weirdness from X or kswapd... it's just that some drivers are better than others. And right now, it looks like Windows drivers are 5% to 40% better than Linux drivers. Frankly, since Windows sales are 500% to 40000% better than Linux sales, I'm not complaining about driver quality.

I am surprised to see the 3Dfx drivers do so poorly, though. Isn't anyone helping out Daryll Strauss now that we've got source code available?

But of course, just how much can you trust the benchmarks? They ran it on one game, using a particular configuration, for a specific kernel.

Well, aside from the usual difficulties, there was one special case; the Matrox testing was done using full OpenGL drivers under Linux and a specific Quake 3 "TurboGL" driver under Windows; TurboGL drivers are Matrox's OpenGL subsets designed to run one game per DLL. In fact, the TurboGL driver postdates the Linux Mesa drivers; at one time (and probably still) the Linux implementation was significantly faster than the full Matrox OpenGL.

Re:Inherent performance limitations for 3D?

[amccall]

In a very definiate way....

Under Windows you're drivers can talk near directly to the hardware, and their are less layers of protection slowing things down. Under Linux, their are more layers of protection between the hardware and the drivers, not to mention things have to talk more directly to a windowing system like X.

This means that in general linux games, etc.. will be more stable than their Windows equivalents, and if they crash, again in general, your system should be able to survive. (Even if you have to telnet in and reboot.)

Here's where DRI and XFree 4.0 come in. With DRI a driver can talk much more directly to the hardware, and generally speed things up, and provide more features.

So in Windows you get a slight speed increase in drivers at the sacrifice of stability. Of course, anything dealing with hardware/drivers can cause complete system lockups, its just less likely in Windows than in Linux.

A better comparison would be either Linux to NT 4.0, or Linux with XFree 4.0 to Windows 2000.

As it stands, you can get a nice idea of the slowdown by the GeForce drivers, which are ownly slightly faster in Windows than in linux. Of other note, is that the drivers in Linux are not optimized for games, as the article brought out several times. It would be VERY interesting to see some Linux vs. NT/2000 benchmarks in workstation operations(cad/design/etc...)

Measure of Support not Performance

[sterno]

Really this demonstration indicates the disparity between Windows and Linux for support by vendors, not the actual power of the O/S. If you ran a similar comparison of Mac vs. Windows you would probably see similar results. It's not because Windows is superior its because 90% of the market earns you 90% of the developer time.

As Linux grows because of its capabilities in other areas and its openness, it will gain market share, and the disparity between the two will decrease. Just give it time :)

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