Re: code bloat [was Re: Semaphore assembly-code bug]

[Alan Cox]

On Sul, 2004-10-31 at 20:18, Z Smith wrote:
> My laptop's framebuffer is only 800x600x24bpp VESA, or 1406kB.
> But look at what X is doing:

X has the frame buffer mapped as reported by VESA sizing not the 
minimal for the mode. (Think about RandR and you'll see why)

> root       632  6.1 17.5 22024 16440 ?       S    12:05   0:17 X :0
> 
> The more apps in use, the more memory is used, but at the moment
> I've only got xterm, rxvt, thunderbird, xclock and xload. My wm is
> blackbox which is using 5 megs.

Mostly shared with the other apps, you did remember to divide each page
by the number of users ?

> Also, just curious but why would memory-mapped I/O be counted
> in the memory usage anyway? Shouldn't there be a separate number
> for framebuffer memory and the like?

Actually there is probably not enough information in /proc to do the
maths on it. The kernel itself has a clear idea which vma's are not
backed by ram in the usual sense as they are marked VM_IO.

> > I've helped write tiny UI kits (take a look at nanogui for example) but
> > they don't have the flexibility of X.
> 
> In my experience, most of the flexibility is not necessary for
> 97% of what I do, yet it evidently costs a lot in memory usage
> and speed.

So my X server is 1Mb larger because I can run networked apps and play
bzflag. Suits me as a tradeoff - I'm not saying it always is the right
decision - nanogui works well in restricted environments like video
recorders for example.

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