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

[Rich Felker]

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

Rich