I'm running tf2 on a laptop with Fedora 21 with Comanglia's Config and it runs fine, but it would probably run better in windows having directx support.

paging perfect_number

I sometimes play pubs and mge on my linux install, there are several issues though:

The proprietary AMD driver sucks but offers much better 3D acceleration, however there are 2D performance issues which is not an issue with the open source driver plus the AMD proprietary driver has some stability issues.

If you are using NVIDIA the drivers are much better, however, if you use a distro like ubuntu or it's derivatives the driver version lacks several releases behind using the official software repositories.

Want to disable moue accel? have fun disabling it using 'xinput' using the terminal and adding the commands to a startup script. Even if you do this you probably won't get 1:1 sens with windows unless your mouse has a physical button to disable accel and you are using rawinput. Any mouse vendor that uses software to disable accel such as logitech you won't be able to disable accel using rawinput and you have to rather disable accel in X windows instead using xinput but adds increased input latency.

Same thing if you have a 120hz monitor it defaults to 60hz and then using 'xrandr' in the terminal to set the refresh rate as the gnome software control centre in particular doesn't expose the option to change the refresh rate.

Despite all that I recommend you dual boot/ try on another machine and test it out you may have a much better experience than me. However, don't expect the linux versions of games to be ready for competitive play but it is good enough for pubs and casual play.

edit: I just realized I didn't actually answer your question about performance. Expect about a ~10% performance decrease from the game converting directX calls to OpenGL. However, there are so many variables such as drivers, hardware, mesa version, etc that you may get better performance, worse or about the same.

I always thought that only Wine and similar software does this work and TF2 uses OpenGL without any conversion layers. Am I right?

If you play on nvidia like me there's basically no difference between the windows and linux versions performance, back when the linux version first came out it actually ran MUCH better than the windows version (on nvidia anyways, I don't think good amd drivers existed back then), but 200 updates later it runs just as badly as the windows version.

Additionally if you use a bunch of mods in the custom folder it increases game startup time to a minute on linux, but lots of mods in general decreases performance anyways.

tl;dr windows will be faster, but linux will still work.

Sorted worst to best performance: linux with ssd, win7 with hdd, win8 with ssd.
Sorted lowest to highest loading times: win7 with hdd, linux with ssd, win8 with ssd.
That being said, I play with a high-tier CPU, mid/high tier GPU, and Chris' maxframes. I get 1000+ fps in win8, and maybe 300-500+ in linux--although this might just be linux/opengl/windows manager/X11/whatever not wanting to run at absurdly high frames.

Linux tf2/csgo will be buggy; I've had crashes, many problems with chat input, glitchy focus (on my windows manager at least), and some other things that have been patched by now. Also, no PREC :(
Disabling mouse accel was pretty easy; I just edited one config file: https://wiki.archlinux.org/index.php/Mouse_acceleration#Disabling_mouse_acceleration
Feel free to ask if you want Linux configuration help.

paging omp

I find that I have similar frames using the proprietary nvidia drivers and linux RT kernel

I can do some concrete benchmarks later if you want - I have an essay to write atm though

Using Ubuntu GNOME, ive noticed about a 30-60 FPS Boost using a OC'ed Pentium G3258 to 4.1 hz and GTX 750 Ti using the latest drivers. The only reason I dont use GNOME is because of the fact Linux calculates its mice a lot differently making your mouse a lot more sensitive even using the same DPI. And I don't want to mess with settings to get my same In/360

yeah I manually measured the inches/360/dpi, unfortunately the relationship isn't linear - I ended up with something that's pretty close though

The one time I used linux for TF2 I had noticeably lower input lag despite having half the frames. Take that how you will.

Where can I get RT patches?

If you can, make it with m0re config without compositors (or Aero) and any open userspace programs (excluding WM) with Debian kernel (3.16.2-3) or on Windows 7. Thanks in advance.

I use arch, so I just used ABS. I don't know if debian has something similar, but you'll probably have to compile it manually - see https://rt.wiki.kernel.org/index.php/RT_PREEMPT_HOWTO.

I'll do the configs, but I'm not going to switch kernels/compositors/windowsversion.

WINE converts every single Windows call to a Linux-compatible one, which does often include its own DirectX implementation that remaps to OpenGL. However, that's more of a brute force method. If I recall correctly, Source on non-Windows platforms does map DirectX to OpenGL itself, though because it handles that itself without some wonky compatibility layer, it's going to perform a lot better and have fewer issues.

I believe this is why the Orange Box was on the 360 directly from Valve, while the PS3 version actually had EA as a developer, on top of being the publisher (EA published both). EA was in charge of working on the OpenGL remapping for the PS3, which only runs OpenGL, but the game worked just fine on the 360 which supported DirectX.

I'm on Gentoo with debian-sources with binary USE flag and I never configured a kernel successfully, I always failed. And I have no /proc/config.gz. What should I do to get current configuration?

try /boot/config or /usr/src/linux-n/.config

pretty sure gentoo wiki has a page on this

edit: it does, just follow that and USE the CONFIG_PREEMPT_RT patch

Made it, but did not noticed any performance boost, returned to previous kernel.

Maybe nouveau and Gallium Nine with Wine can help me.