[MPlayer-dev-eng] [Patch] swscale on gcc4+amd64

[Guillaume POIRIER]

Hi,

On 6/7/05, Michael Niedermayer <michaelni at gmx.at> wrote:
> Hi
> 
> On Tuesday 07 June 2005 14:54, Rich Felker wrote:
> > On Tue, Jun 07, 2005 at 09:49:06AM +0200, Guillaume POIRIER wrote:
> > > Hi,
> > >
> > > On 6/7/05, Rich Felker <dalias at aerifal.cx> wrote:
> > > > On Sun, Jun 05, 2005 at 02:06:09PM +0000, Mean wrote:
> > > > > Hello
> > > > > The attached patch enabled me to compile postproc/ on amd64 with gcc4
> > > > > and gcc 3.3.5
> > > > > Thanks
> > > >
> > > > I read the asm diffs and they're mostly trivial. It would be nice if
> > > > someone could benchmark this too and make sure it doesn't hurt
> > > > performance, but otherwise I'm ok with it..
> > >
> > > Ivan briefly explained to on IRC me yesterday that ffmpeg featured the
> > > macros START_TIMER("func_name") and STOP_TIMER("func_name"), which
> > > prints the figures on the console.
> > > I think that this will look like something like this:
> > > 2287 dezicycles in loop_vl_16bit, 1048386 runs, 190 skips
> > >
> > > Problem is: I don't know what all those figures mean: I guess we want
> > > "dezicycles" to always be at least the same between 2 runs, or lower
> > > in case the second run is an optimized one.
> > > As for "runs" and "skips", I'm not sure what they mean.
> > >
> > > Ok now, but where am I supposed to put those timer calls? right
> > > *before* an ASM block? At the *beginning* of an ASM block...
> >
> > IMO it won't work. adding timer code in the function itself could
> > easily change how gcc decides to load the registers/addresses for the
> > asm block. Just time the _whole program_ with mplayer -benchmark
> 
> waste of time, its not accurate enough to show small differences ...

So I guess that given the very small difference Rich noticed in the
ASM code, and the inability to be benchmark the difference, all we
have to do is commit this patch to the CVS?

Regards,

Guillaume
-- 
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