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Re: Transparency Behind Launcher Option

 

On Fri, 25 May 2012, Ryan Gauger wrote:

It doesn't hurt to try. Transparency in Windows 7 usually makes the computer run slower, but makes too little of a difference to be noticeable. My guess would be that this same thing happens in Unity. Even though it may be unnoticeable if this is the case, it still matters, because there are people who run tests of speed and performance and put those online and make blog posts about them. I am thinking if anybody or blog would do that, it would probably be OMG! Ubuntu! Thanks!!!


I feel like we're straying off topic (this is the design list, not the development list). However, I want to clarify this before people become
misinformed.

Transparency does have a cost, however disabling it wouldn't be of much effect. Disabling it does allow you to do things like out of order rendering, however the kind of rendering work that unity does when it isn't doing things like lighting or gaussian blurs is so cheap that you wouldn't see a difference.

Transparency in windows comes at a cost because of the fact that you're doing surface blurs (eg, synchronous operation using the DX equavilent for glCopyTexSubImage2D or binding of framebuffer objects mid-render-pipe as well as fragment shaders doing about 9 texture samples per pixel). Especially on low end hardware where you don't have a lot of shader cores and can't parallelize this stuff very easily (eg, intel) this comes at a cost.

If you want real performance gains, the best way to do it is to profile using tools like callgrind or gprof or the like. For example, a couple of months ago in compiz we found that we were creating about 200,000 regions for paint calculation - first we optimzied by reducing the expensive part of this (memory allocation) and secondly we optimized by reducing the number of regions that needed to be created in order to do paint area calculation.

If you wish to contribute in this area, there are plenty of guides as to how to use callgrind to get useful analytics - contributions would be much appreciated because the developers don't have access to all the hardware and every possible configuration that there might be. In addition, running under callgrind is time-consuming because it slows down operation about 20x while it looks for hot-spots in the code.

Cheers,

Sam

On May 25, 2012, at 3:43 AM, Mikkel Kamstrup Erlandsen <mikkel.kamstrup@xxxxxxxxxxxxx> wrote:

On 05/24/2012 03:28 PM, Ryan Gauger wrote:
Hi Team,

I just had an idea that may speed up Unity even further. We could
perhaps make transparency behind the launcher an option, so that if
users choose to disable it, their computer's performance and speed
should run a bit smoother. Just an idea :) Thanks!

Sorry, do you have any data to back up the argument that anything would be measurably faster with launcher transparency disabled? Without any hint of evidence I don't think this is worth spending time on.

Don't get me wrong, I'd love to make everything perform better, but we need a way to gauge this rigorously, otherwise we're shooting in the dark.

Cheers,
Mikkel

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