[PATCH] drm/radeon: Inline r100_mm_rreg, v2

[Christian König]

Am 18.04.2014 23:11, schrieb Lauri Kasanen:
> This was originally un-inlined by Andi Kleen in 2011 citing size concerns.
> Indeed, a first attempt at inlining it grew radeon.ko by 7%.
>
> However, 2% of cpu is spent in this function. Simply inlining it gave 1% more fps
> in Urban Terror.
>
> v2: We know the minimum MMIO size. Adding it to the if allows the compiler to
> optimize the branch out, improving both performance and size.
>
> The v2 patch decreases radeon.ko size by 2%. I didn't re-benchmark, but common sense
> says perf is now more than 1% better.

Nice!

But are you sure that the register PCI bar is always at least 64K in 
size? Keep in mind that this code is used over all generations since 
R100. Additional to that we probably should have a define for that and 
also apply the optimizations to r100_mm_wreg as well.

Christian.

>
> Signed-off-by: Lauri Kasanen <cand at gmx.com>
> ---
>   drivers/gpu/drm/radeon/r100.c   | 18 ------------------
>   drivers/gpu/drm/radeon/radeon.h | 21 +++++++++++++++++++--
>   2 files changed, 19 insertions(+), 20 deletions(-)
>
> The _wreg function could be given similar treatment, but as it's nowhere as hot
> (0.009% vs 2%), didn't bother.
>
> diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
> index b6c3264..8169e82 100644
> --- a/drivers/gpu/drm/radeon/r100.c
> +++ b/drivers/gpu/drm/radeon/r100.c
> @@ -4086,24 +4086,6 @@ int r100_init(struct radeon_device *rdev)
>   	return 0;
>   }
>   
> -uint32_t r100_mm_rreg(struct radeon_device *rdev, uint32_t reg,
> -		      bool always_indirect)
> -{
> -	if (reg < rdev->rmmio_size && !always_indirect)
> -		return readl(((void __iomem *)rdev->rmmio) + reg);
> -	else {
> -		unsigned long flags;
> -		uint32_t ret;
> -
> -		spin_lock_irqsave(&rdev->mmio_idx_lock, flags);
> -		writel(reg, ((void __iomem *)rdev->rmmio) + RADEON_MM_INDEX);
> -		ret = readl(((void __iomem *)rdev->rmmio) + RADEON_MM_DATA);
> -		spin_unlock_irqrestore(&rdev->mmio_idx_lock, flags);
> -
> -		return ret;
> -	}
> -}
> -
>   void r100_mm_wreg(struct radeon_device *rdev, uint32_t reg, uint32_t v,
>   		  bool always_indirect)
>   {
> diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
> index f21db7a..883276a 100644
> --- a/drivers/gpu/drm/radeon/radeon.h
> +++ b/drivers/gpu/drm/radeon/radeon.h
> @@ -2328,8 +2328,25 @@ int radeon_device_init(struct radeon_device *rdev,
>   void radeon_device_fini(struct radeon_device *rdev);
>   int radeon_gpu_wait_for_idle(struct radeon_device *rdev);
>   
> -uint32_t r100_mm_rreg(struct radeon_device *rdev, uint32_t reg,
> -		      bool always_indirect);
> +static inline uint32_t r100_mm_rreg(struct radeon_device *rdev, uint32_t reg,
> +				    bool always_indirect)
> +{
> +	/* The mmio size is 64kb at minimum. Allows the if to be optimized out. */
> +	if ((reg < rdev->rmmio_size || reg < 0x10000) && !always_indirect)
> +		return readl(((void __iomem *)rdev->rmmio) + reg);
> +	else {
> +		unsigned long flags;
> +		uint32_t ret;
> +
> +		spin_lock_irqsave(&rdev->mmio_idx_lock, flags);
> +		writel(reg, ((void __iomem *)rdev->rmmio) + RADEON_MM_INDEX);
> +		ret = readl(((void __iomem *)rdev->rmmio) + RADEON_MM_DATA);
> +		spin_unlock_irqrestore(&rdev->mmio_idx_lock, flags);
> +
> +		return ret;
> +	}
> +}
> +
>   void r100_mm_wreg(struct radeon_device *rdev, uint32_t reg, uint32_t v,
>   		  bool always_indirect);
>   u32 r100_io_rreg(struct radeon_device *rdev, u32 reg);