Raspberry pi - is this slow?


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by yrrebpsarip » Sat May 26, 2012 5:10 pm
Hello ,
I set up my raspberry pi with "debian(squeeze) today" , and the speed the device ran at seemed "un-usually slow" even for a relatively low end device.
I have two questions :

Is the speed that my pi is running at normal ( examples of slowness include : taking about 4 seconds to load up a simple file explorer program , when drawing "rectangles" on desktop to select things it lags behind quite significantly , and when clicking on dialogue boxes it often takes a frustratingly large time to highlight them ).

I have seen the pi run xmbc and quake 3 , so am therefore prompted to ask if this speed is normal or not on my pi?

Also , how do you get the pi to boot straight into a gui and prompt for password and username rather than the "terminal " type window /bios asking for passwords ?

Thanks for the help . :)
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by cheery » Sat May 26, 2012 6:28 pm
You need to get some display manager which provides a login screen. lxde? Add a related script into your system init and it should do. I don't know further specifics though.

Have you tried examples in /opt/vc/src ? Do they run properly? My quick guess is that configuration might reserve too small chunk of memory for videocore.
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by Grumpy Mike » Sat May 26, 2012 7:52 pm
Is the speed that my pi is running at normal

Looks like it, it is the sort of thing I am getting.
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by ehjp » Mon Jun 04, 2012 3:34 pm
I am really disappointed by the speed of the Debian Squeeze image - exactly the same issues as "yrrebpsarip" had.

Clicking a URL in Google seems to eat 100% CPU for 5 seconds - surely this isn't right?

Has anyone got any ideas what can be done to improve this - is there a better distro to use? Otherwise the Pi is unusable, which is not a good place to be...
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by mahjongg » Mon Jun 04, 2012 5:19 pm
  • install and use another browser, I.E. Chromium
  • Use a lower resolution screen mode (less pixels to push around by the CPU)
  • Use another distro (I have high hope for puppy linux, and also RiscOS)
  • Wait for the many possible optimizations, such as hardware floating point, and GPU screen drawing support
  • Overclock the PI

In the end, the PI will never become "fast", but certainly the last point of the list should help.
The PI isn't and never was intended as a cheap PC replacement, so it also what you expect of it.
So "reset your expectations"!
It is a cheap and cheerful "throw away" computer for kids to learn programming on, (including modern techniques such as 3D rendering) and is basically comparable with a 15 year old PC, (200 MHz pentium Pro, remember those?) with a modern "video card", (but for 2D at the moment it is used as a simple non hardware accelerated "VGA video card") connected to a very high resolution screen, so that until 2D acceleration is implemented the CPU has to move massive amounts of pixels itself, (which no modern computer needs to do) and running the "lite versions" of modern software.
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by Scotty T » Mon Jun 04, 2012 5:30 pm
I'm not sure if you guys realize yet. We are waiting for the development of the video accelerator driver. The GPU is not being used in X windows so the CPU is doing all the processing for video.
As soon as we see a driver for the GPU the performance will change dramatically. Until the GPU is basically doing nothing.
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by abishur » Mon Jun 04, 2012 5:38 pm
As Scotty said, the x gui is not making use of the GPU acceleration. I do think that once we clear that little hurdle people will start viewing as a more acceptable desktop device, but there will always be some people find the speed lacking. Que sera! :roll:
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by ehjp » Tue Jun 05, 2012 8:39 am
Thanks everyone for the replies - the CPU/GPU thing makes sense, I suspect that was kept quiet in the press launches when the Pi was rendering 30 frames per second!
At least I can now continue knowing that this isn't some hardware issue.

Will be good to get the GPU drivers - any ideas when they are going to be released?
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by abishur » Tue Jun 05, 2012 3:24 pm
ehjp wrote:Thanks everyone for the replies - the CPU/GPU thing makes sense, I suspect that was kept quiet in the press launches when the Pi was rendering 30 frames per second!
At least I can now continue knowing that this isn't some hardware issue.

Will be good to get the GPU drivers - any ideas when they are going to be released?


Unfortunately not, I think the goal is before the educational release, but well see. I do know that there is a lot of work being poured into the pi on a lot of fronts, so even if you can't make use of the x environment right now, there are a lot of other fun things you can do with you pi in the mean time ;-)
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by mahjongg » Tue Jun 05, 2012 4:12 pm
ehjp wrote:Thanks everyone for the replies - the CPU/GPU thing makes sense, I suspect that was kept quiet in the press launches when the Pi was rendering 30 frames per second!
At least I can now continue knowing that this isn't some hardware issue.

Will be good to get the GPU drivers - any ideas when they are going to be released?


The "rendering 30 frames per second" thing is a completely different thing! The broadcom chip was designed to do 3D rendering (with an OpenGL variant, for games and such), so all the drivers were ready, and thus 3D rendering could be demonstrated with nearly its full potential.

But the "GPU drivers" we are talking about now are for "2D" acceleration of common tasks in x-windows, such as moving a part of the screen (a window), or drawing line, or a box, or filling a rectangular area with a bitmap from elsewhere in memory, or drawing text on the screen, all these tasks are now painstakingly done with the CPU, and the amount of work is enormous, as a full (for example full-HD) 1920 x 1080 pixel screen has 2 million pixels, each pixel is represented by two (or four) bytes, so to draw such a screen the CPU has to set 4 to 8 million bytes!
In retrospect, any modern CPU only has to tell the hardware in the video card to manipulate these millions of bytes, and the GPU does it, much faster than the CPU ever could.

The moment the PI can also delegate these tasks to the GPU (which is relatively much more powerful than the CPU in the PI) the whole thing will behave much faster, especially for drawing intensive tasks.

The relative performance of the GPU versus CPU is very different on a PI than it is on a modern PC, the PI has a relatively weak CPU, but an enormously powerful GPU, at the moment we are only using the weak CPU, the powerful GPU is still unused (unless we use it to render 3D pictures, or video).
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by cheery » Tue Jun 05, 2012 7:30 pm
If the GPU is the muscle of pi, why didn't they provide opencl drivers?
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by BlowingRaspberries » Wed Jun 06, 2012 9:14 am
Remember, initially the first boards were supposed to be 'developer releases' really - the huge media/viral/hype machine took over and hundreds of thousands ordered one.

I remember years back running SUSE on a Celeron and it was pretty darned slow until I finally managed to get drivers for my Nvidia card working - it was then night and day. That said, it's hard to how useful a 'day to day' machine a Pi will be with limited memory and a modest processor - I think Android, or even RISC OS, will be better bets for people looking to do general productivity on it and have a 'fun gizmo'.

Mine is running like a champ as a headless command-line tool (until I made the schoolboy error of not realising I was only using 2GB of my SD card). That's what i wanted it for - to learn and relearn hacky command line stuff.
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by tufty » Wed Jun 06, 2012 9:32 am
cheery wrote:If the GPU is the muscle of pi, why didn't they provide opencl drivers?

Because OpenCL implementations are massively expensive and difficult to develop, and of zero relevance to the 'intended' use of the Broadcom SoC (set top boxes, etc).

OpenCL would only allow acceleration of compute-bound tasks anyway, and would help not a jot wrt interface speed. The issue there is the use of X, which is "non-trivial" to accelerate using anything other than device-level tweaks. If it were otherwise, an OpenGL/ES or OpenVG accelerated X would already exist, and would have existed for some time.

Throwing away X and using something new built on OpenGL/ES or OpenVG, a la OSX or Android, would be do-able (indeed, many of the toolkits already exist, most of the work is already done), but kills compatibility with gui apps under Linux. IMO, X needs to die, but that's a longer term thing than this particular board can aim at solving.

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by andyl » Wed Jun 06, 2012 10:47 am
tufty wrote:IMO, X needs to die, but that's a longer term thing than this particular board can aim at solving.


Well maybe not die. But certainly it needs to become a legacy product.

I'm not sure if Wayland is the answer, but I think that it would be a better solution for the Pi - it is likely to be more performant and smaller than X. Although of course Wayland isn't ready yet so we don't really know.

For those that don't know the X Window System does things differently to most other competitors. It is client/server and network-transparent. If you have two machines it is relatively easy to run a program on one machine and display its windows (and get input) on the other. A few people still feel that this network transparency is really, really, important. I think most people don't really care. The X Window System has also grown rather organically from its origins and kept backwards compatibility (mostly). So quite a few things have been added to improve functionality almost as an afterthought. There is a lot of cruft there.
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by tufty » Wed Jun 06, 2012 5:24 pm
andyl wrote:
tufty wrote:IMO, X needs to die, but that's a longer term thing than this particular board can aim at solving.


Well maybe not die. But certainly it needs to become a legacy product.

I'm not sure if Wayland is the answer, but I think that it would be a better solution for the Pi - it is likely to be more performant and smaller than X. Although of course Wayland isn't ready yet so we don't really know.

For those that don't know the X Window System does things differently to most other competitors. It is client/server and network-transparent. If you have two machines it is relatively easy to run a program on one machine and display its windows (and get input) on the other. A few people still feel that this network transparency is really, really, important. I think most people don't really care. The X Window System has also grown rather organically from its origins and kept backwards compatibility (mostly). So quite a few things have been added to improve functionality almost as an afterthought. There is a lot of cruft there.

Parts of X are beautiful. Parts of it aren't. The beautiful stuff involves the client/server layer, and the way you can get decent GUI performance when your server is somewhere else and only accessible over thinnet. The not-so-beautiful stuff is pretty much everything anyone actually uses on a desktop setup.

Doing away with X would also, in a bound, do away with the horrible UIs of the majority of *n*x GUI applications. Sure, they would be replaced by equally ugly ones, but at least they would be different.
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by andyl » Wed Jun 06, 2012 5:39 pm
tufty wrote:Doing away with X would also, in a bound, do away with the horrible UIs of the majority of *n*x GUI applications. Sure, they would be replaced by equally ugly ones, but at least they would be different.


X itself has very little to do with how *nix GUI applications look. That is the responsibility of the window managers and the applications themselves. Which is why lots of applications look slightly different wrt scrollbars etc.
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