optimizing [was: panning]
optimizing [was: panning]
- Subject: optimizing [was: panning]
- From: Arthur Clemens <email@hidden>
- Date: Mon, 6 May 2002 19:26:14 +0200
Talking about optimizing, are there any Altivec functions that can
optimize writing iteratively to a buffer?
Arthur
On Monday, May 6, 2002, at 05:07 PM, James McCartney wrote:
On Sunday, May 5, 2002, at 04:42 PM, Doug Wyatt wrote:
That's the correct algorithm ... you might find that the code will run
faster by doing two or more samples per loop iteration in order to
give the compiler more room for optimizing with instruction scheduling.
Be careful unrolling loops. Metrowerks' optimizer will unroll loops for
you and if you've unrolled them yourself you may wind up with doubly
unrolled loops including two separate pieces of code to deal with the
remainder, one you wrote and one inserted by the optimizer - a real
mess. Either let the optimizer unroll them or unroll them yourself and
use a pragma to turn off the optimizer's unrolling.
Also I recommend to not use Duff's device.
The switch's case labels put entry points into the unrolled loop,
across which the optimizer cannot reorder instructions. It is better to
use one unrolled loop and one for the remainder. Then the optimizer can
freely reorder instructions inside the unrolled loop.
--
--- james mccartney email@hidden <http://www.audiosynth.com>
SuperCollider - a real time synthesis programming language for the
PowerMac.
<ftp://www.audiosynth.com/pub/updates/SC2.2.14.sea.hqx>
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| References: | |
| | >Re: panning (From: James McCartney <email@hidden>) |