Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

[Ingo Molnar]

* Christer Weinigel <christer@xxxxxxxxxxx> wrote:

> On Tue, 1 Jan 2008 19:46:59 +0100
> Ingo Molnar <mingo@xxxxxxx> wrote:
> 
> > 
> > * Christer Weinigel <christer@xxxxxxxxxxx> wrote:
> > 
> > > What I'm afraid is that udelay will be significantly slower, [...]
> > 
> > why should it be significantly slower?
> 
> out 80h, al is only two bytes.  Any alternative that has been 
> suggested in this discussion will use more space.  mov dx, alt_port; 
> out dx, al will be larger, a function call will definitely be a lot 
> larger. People have been making changes to the kernel to save a couple 
> of hundred bytes of text size.

i've done dozens of patches that saved much less of text size, so yes, i 
very much care about code size. But it has been stated in this thread 
that most of the _p() API uses in the kernel today are bogus. So 
eventually getting rid of the bogus ones will be a net code size 
_reduction_. (But even that is besides the point, we prefer clean and 
easier to maintain code.)

> I don't know if the difference in code size or the udelay will be 
> significantly slower, but I think it might be.

ok, "I dont know but it might be slower" is a perfectly fine statement 
instead of your original "it will be slower".

	Ingo
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