Re: [Linux-fbdev-devel] Re: [BK FBDEV] String drawing optimizations.

[Geert Uytterhoeven]

On Thu, 15 May 2003, James Simmons wrote:
> > What about getting rid of one-char putc, implementing it in terms of
> > putcs? I'm doing it in matroxfb patches, and nobody complained yet, and
> > with current length of {fbcon,accel}_putc{s,} I was not able to find
> > measurable speed difference between putc and putc through putcs variants.
> 
> Hm. I compressed all the image drawing functions into accel_putcs which is 
> used in many places. I then placed accel_putc() into fbcon_putc(). I could 
> have accel_putcs() called in fbcon_putc(). The advantage is smaller 
> amount of code. The offset is a big more overhead plus a function call. 
> What do people think here?

putc() is almost never called, IIRC. We did our best to combine as much data as
possible and call putcs().

A quick grep showed ->con_putc() is called only in drivers/char/vt.c for:
  - Complementing the pointer position (for gpm)
  - Inserting/deleting single characters
  - Softcursor

I guess the small overhead won't have much influence here.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [e-mail]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds