Re: [PATCH 11/12] i915: Move i915_read/write out of line

[Ben Widawsky]

On Thu, 13 Oct 2011 16:08:51 -0700
Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:

> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> 
> With the tracing code in there they are far too big to inline.
> 
> .text savings compared to a non force inline kernel:
> 
> i915_restore_display                        4393   12036   +7643
> i915_save_display                           4295   11459   +7164
> i915_handle_error                           2979    6666   +3687
> i915_driver_irq_handler                     2923    5086   +2163
> i915_ringbuffer_info                         458    1661   +1203
> i915_save_vga                                  -    1200   +1200
> i915_driver_irq_uninstall                    453    1624   +1171
> i915_driver_irq_postinstall                  913    2078   +1165
> ironlake_enable_drps                         719    1872   +1153
> i915_restore_vga                               -    1142   +1142
> intel_display_capture_error_state            784    2030   +1246
> intel_init_emon                              719    2016   +1297
> 
> and more ...
> 
> [AK: these are older numbers, with the new SNB forcewake checks
> it will be even worse]
> 
> Cc: keithp@xxxxxxxxxx
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/i915/i915_drv.c |   40 +++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/i915_drv.h |   22 ++------------------
>  2 files changed, 43 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index f07e425..c2de142 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -895,3 +895,43 @@ module_exit(i915_exit);
>  MODULE_AUTHOR(DRIVER_AUTHOR);
>  MODULE_DESCRIPTION(DRIVER_DESC);
>  MODULE_LICENSE("GPL and additional rights");
> +
> +/* We give fast paths for the really cool registers */
> +#define NEEDS_FORCE_WAKE(dev_priv, reg) \
> +	(((dev_priv)->info->gen >= 6) && \
> +	((reg) < 0x40000) && \
> +	((reg) != FORCEWAKE))
> +
> +#define __i915_read(x, y) \
> +u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
> +	u##x val = 0; \
> +	if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
> +		gen6_gt_force_wake_get(dev_priv); \
> +		val = read##y(dev_priv->regs + reg); \
> +		gen6_gt_force_wake_put(dev_priv); \
> +	} else { \
> +		val = read##y(dev_priv->regs + reg); \
> +	} \
> +	trace_i915_reg_rw(false, reg, val, sizeof(val)); \
> +	return val; \
> +}
> +
> +__i915_read(8, b)
> +__i915_read(16, w)
> +__i915_read(32, l)
> +__i915_read(64, q)
> +#undef __i915_read
> +
> +#define __i915_write(x, y) \
> +void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
> +	trace_i915_reg_rw(true, reg, val, sizeof(val)); \
> +	if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
> +		__gen6_gt_wait_for_fifo(dev_priv); \
> +	} \
> +	write##y(val, dev_priv->regs + reg); \
> +}
> +__i915_write(8, b)
> +__i915_write(16, w)
> +__i915_write(32, l)
> +__i915_write(64, q)
> +#undef __i915_write
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 7916bd9..7d171ea 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1354,18 +1354,7 @@ void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv);
>  	((reg) != FORCEWAKE))
>  
>  #define __i915_read(x, y) \
> -static inline u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
> -	u##x val = 0; \
> -	if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
> -		gen6_gt_force_wake_get(dev_priv); \
> -		val = read##y(dev_priv->regs + reg); \
> -		gen6_gt_force_wake_put(dev_priv); \
> -	} else { \
> -		val = read##y(dev_priv->regs + reg); \
> -	} \
> -	trace_i915_reg_rw(false, reg, val, sizeof(val)); \
> -	return val; \
> -}
> +	u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg);
>  
>  __i915_read(8, b)
>  __i915_read(16, w)
> @@ -1374,13 +1363,8 @@ __i915_read(64, q)
>  #undef __i915_read
>  
>  #define __i915_write(x, y) \
> -static inline void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
> -	trace_i915_reg_rw(true, reg, val, sizeof(val)); \
> -	if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
> -		__gen6_gt_wait_for_fifo(dev_priv); \
> -	} \
> -	write##y(val, dev_priv->regs + reg); \
> -}
> +	void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val);
> +
>  __i915_write(8, b)
>  __i915_write(16, w)
>  __i915_write(32, l)

Acked-by: Ben Widawsky <ben@xxxxxxxxxxxx>

The forcewake increased size should have been fixed a bit with the
forcewake struct encapsulation patch I posted to intel-gfx mailing list.
Keith, if you take this, could you also look into that patch?
<1315951648-5380-1-git-send-email-ben@xxxxxxxxxxxx>
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