Messages in this thread | | | Date | Thu, 30 Dec 1999 15:05:16 +0000 (GMT) | From | Dave Jones <> | Subject | Re: 3DNow! patches on Winchip. |
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On Thu, 30 Dec 1999, Alan Cox wrote:
> Make sure you benchmark both the cached and uncached cases.
I did a test copying large amounts of memory around in 64kb chunks..
Cached: 3dnow : 25 secs integer : 3 minutes
Non-Cached: 3dnow : 75 secs integer : (Still running on another box after ~15 minutes)
> If it is definitely a win to use the 3dnow code then use it.
I think the above figures speak for themselves. Remember, I'm not running this on the correct bus speed, so the proper benchmark will probably be much higher.
> Note that there is some stuff pending (hopefully for 2.4.0) that > allows you to plug in multiple memcpy routines and handle the choice > per cpu.
That sounds great. How will these be selected, by an extra menu in the config ?
> That will also allow you to do finer tuning for the winchip.
Since my initial posting, I read that on the the Winchip 2A the prefetch instruction is treated as a nop. Eliminating these from the routine gains a few more benchmarks. Would that then make it the same as the MMX-copy ?
> Right now with the current draft of that code it has support for
Is this already in 2.3.x ?
regards,
Dave.
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