2020-05-28 17:09:32

by Sidong Yang

Subject: [PATCH] drm/kms: Optimize compute_crc(), blend()

Hi Daniel,

I'm newbie in linux kernel and interested in drm module.
Please check this patch and give some advice for me.
I want to participate in developing kernel and community.

Thanks,

Sidong

Optimize looping pixels in compute_crc() and blend(). Calculate
src_offset in start of looping horizontally and increase it.
It's better than calculating in every pixels.

Signed-off-by: Sidong Yang <[email protected]>
---
drivers/gpu/drm/vkms/vkms_composer.c | 32 +++++++++++++++-------------
1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
index 4af2f19480f4..9d2a765ca1fb 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -28,14 +28,14 @@ static uint32_t compute_crc(void *vaddr_out, struct vkms_composer *composer)
u32 crc = 0;

for (i = y_src; i < y_src + h_src; ++i) {
- for (j = x_src; j < x_src + w_src; ++j) {
- src_offset = composer->offset
- + (i * composer->pitch)
- + (j * composer->cpp);
+ src_offset = composer->offset + (i * composer->pitch)
+ + (x_src * composer->cpp);
+ for (j = 0 ; j < w_src; ++j) {
/* XRGB format ignores Alpha channel */
memset(vaddr_out + src_offset + 24, 0, 8);
crc = crc32_le(crc, vaddr_out + src_offset,
sizeof(u32));
+ src_offset += composer->cpp;
}
}

@@ -61,7 +61,7 @@ static void blend(void *vaddr_dst, void *vaddr_src,
struct vkms_composer *dest_composer,
struct vkms_composer *src_composer)
{
- int i, j, j_dst, i_dst;
+ int i, j, i_dst;
int offset_src, offset_dst;

int x_src = src_composer->src.x1 >> 16;
@@ -73,21 +73,23 @@ static void blend(void *vaddr_dst, void *vaddr_src,
int w_dst = drm_rect_width(&src_composer->dst);

int y_limit = y_src + h_dst;
- int x_limit = x_src + w_dst;

- for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
- for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
- offset_dst = dest_composer->offset
- + (i_dst * dest_composer->pitch)
- + (j_dst++ * dest_composer->cpp);
- offset_src = src_composer->offset
- + (i * src_composer->pitch)
- + (j * src_composer->cpp);
+ for (i = y_src, i_dst = y_dst; i < y_limit; ++i, ++i_dst) {
+ offset_dst = dest_composer->offset
+ + (i_dst * dest_composer->pitch)
+ + (x_dst * dest_composer->cpp);

+ offset_src = src_composer->offset
+ + (i * src_composer->pitch)
+ + (x_src * src_composer->cpp);
+
+ for (j = 0; j < w_dst; ++j) {
memcpy(vaddr_dst + offset_dst,
vaddr_src + offset_src, sizeof(u32));
+
+ offset_dst += dest_composer->cpp;
+ offset_src += src_composer->cpp;
}
- i_dst++;
}
}

--
2.17.1