Re: [Dri-devel] [PATCH] cpu_relax whilst in busy-wait loops.

[Michel Dänzer]

On Mon, 2003-08-11 at 15:40, davej@xxxxxxxxxx wrote: 
> diff -urpN --exclude-from=/home/davej/.exclude bk-linus/drivers/char/drm/gamma_dma.c linux-2.5/drivers/char/drm/gamma_dma.c
> -- bk-linus/drivers/char/drm/gamma_dma.c	2003-05-31 15:58:40.000000000 +0100
> +++ linux-2.5/drivers/char/drm/gamma_dma.c	2003-05-29 14:07:46.000000000 +0100
> @@ -44,9 +44,14 @@ static inline void gamma_dma_dispatch(dr
>  	drm_gamma_private_t *dev_priv =
>  				(drm_gamma_private_t *)dev->dev_private;
>  	mb();
> -	while ( GAMMA_READ(GAMMA_INFIFOSPACE) < 2);
> +	while ( GAMMA_READ(GAMMA_INFIFOSPACE) < 2)
> +		cpu_relax();
> +

[...]

Are you actually using the gamma driver? :) Something like this might be
useful in other drivers as well?


-- 
Earthling Michel DÃnzer   \  Debian (powerpc), XFree86 and DRI developer
Software libre enthusiast  \     http://svcs.affero.net/rm.php?r=daenzer

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