Re: dsound mixer speedup

[Joerg Mayer]

On Thu, Aug 12, 2004 at 12:24:20AM -0400, Robert Reif wrote:
> Speed up mixing and unmixing by moving sample size and buffer
> wrap tests to outside the loop.  The code is not as compact or 
> pretty
> but it should be faster.

Just out of curiosity: *IS* it really faster? Maybe gcc already did
the optimization?

 Ciao
   Joerg

-- 
Joerg Mayer                                           <jmayer(a)loplof.de>
We are stuck with technology when what we really want is just stuff that
works. Some say that should read Microsoft instead of technology.

dsound mixer speedup

[Robert Reif]

Joerg Mayer wrote:
> On Thu, Aug 12, 2004 at 12:24:20AM -0400, Robert Reif wrote:
> > Speed up mixing and unmixing by moving sample size and buffer
> > wrap tests to outside the loop.  The code is not as compact or 
> > pretty
> > but it should be faster.
>
> Just out of curiosity: *IS* it really faster? Maybe gcc already did
> the optimization?
>
> Ciao
>   Joerg

for both 8 and 16 bit samples (no optimization)
    the new code executes in about 48% of the time of the old code 
(twice as fast)

8 bit -O3
   75% of old code (1.5 times as fast)

16 bit -O3
  50% of old code (twice as fast)

This is with a 32k buffer and a 1k chunk size.