[PATCH 01/12] drm: Inline drm_color_lut_extract()

Ville Syrjala
2019-11-07T15:17:35Z

This thing can get called several thousand times per LUT
so seems like we want to inline it to:
- avoid the function call overhead
- allow constant folding

A quick synthetic test (w/o any hardware interaction) with
a ridiculously large LUT size shows about 50% reduction in
runtime on my HSW and BSW boxes. Slightly less with more
reasonable LUT size but still easily measurable in tens
of microseconds.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
drivers/gpu/drm/drm_color_mgmt.c | 24 ------------------------
include/drm/drm_color_mgmt.h | 23 ++++++++++++++++++++++-
2 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index 4ce5c6d8de99..19c5f635992a 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -108,30 +108,6 @@
* standard enum values supported by the DRM plane.
*/

-/**
- * drm_color_lut_extract - clamp and round LUT entries
- * @user_input: input value
- * @bit_precision: number of bits the hw LUT supports
- *
- * Extract a degamma/gamma LUT value provided by user (in the form of
- * &drm_color_lut entries) and round it to the precision supported by the
- * hardware.
- */
-uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision)
-{
- uint32_t val = user_input;
- uint32_t max = 0xffff >> (16 - bit_precision);
-
- /* Round only if we're not using full precision. */
- if (bit_precision < 16) {
- val += 1UL << (16 - bit_precision - 1);
- val >>= 16 - bit_precision;
- }
-
- return clamp_val(val, 0, max);
-}
-EXPORT_SYMBOL(drm_color_lut_extract);
-
/**
* drm_crtc_enable_color_mgmt - enable color management properties
* @crtc: DRM CRTC
diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
index d1c662d92ab7..069b21d61871 100644
--- a/include/drm/drm_color_mgmt.h
+++ b/include/drm/drm_color_mgmt.h
@@ -29,7 +29,28 @@
struct drm_crtc;
struct drm_plane;

-uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision);
+/**
+ * drm_color_lut_extract - clamp and round LUT entries
+ * @user_input: input value
+ * @bit_precision: number of bits the hw LUT supports
+ *
+ * Extract a degamma/gamma LUT value provided by user (in the form of
+ * &drm_color_lut entries) and round it to the precision supported by the
+ * hardware.
+ */
+static inline u32 drm_color_lut_extract(u32 user_input, int bit_precision)
+{
+ u32 val = user_input;
+ u32 max = 0xffff >> (16 - bit_precision);
+
+ /* Round only if we're not using full precision. */
+ if (bit_precision < 16) {
+ val += 1UL << (16 - bit_precision - 1);
+ val >>= 16 - bit_precision;
+ }
+
+ return clamp_val(val, 0, max);
+}

void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
uint degamma_lut_size,