Re: Fwd: Re: still no accelerated X ($#!$*)

On Thu, 20 Jan 2000, Kevin Hendricks wrote:

quoted

I actually doubt that the eieio are necessary but then I'm not a
specialist on this kind of hardware. Every eieio is a bus broadcast
operation (except on 603, on G3 it is IIRC an option controlled by a bit
in HID0) and actually has a cost comparable to a write posted I/O access
but the other consequences (preventing bursts on the I/O bus) may actually
cause a significant performance hit.  So it should be used only when
necessary...

quoted

Please let me know how to change the above so that I get it right this time.

Try to determine first whether the eieio are necessary; for access to the
frame buffer I'm almost sure that they are superfluous and potentially
very costly in terms of performance. For the MMIO I suspect that they may
be necessary at some places, but adding them systematically will have less
impact.

Okay, I went and looked at the latest aty128fb.c code and it does not use eieio
anywhere.  I looked at ealier verions of this file and it at one time had eieio
but they have since been removed.

Perhaps they were replaced by the platform independent wmb()?

Gr{oetje,eeting}s,
--
Geert Uytterhoeven -- Linux/{m68k~Amiga,PPC~CHRP} -- geert@linux-m68k.org

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


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