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neon variance: process 16 values at a time

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Read in a Q register. Works on blocks of 16 and larger.

Improvement of about 20% for 64x64. The smaller blocks are faster, but
don't have quite the same level of improvement. 16x32 is only about 5%

BUG=webm:1422

Change-Id: Ie11a877c7b839e66690a48117a46657b2ac82d4b
This commit is contained in:
Johann 2017-05-01 14:10:54 -07:00 committed by Johann Koenig
parent 1814463864
commit f7d1486f48
1 changed files with 48 additions and 35 deletions
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83
vpx_dsp/arm/variance_neon.c
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@ -32,34 +32,47 @@ static INLINE int horizontal_add_s32x4(const int32x4_t v_32x4) {
}
// w * h must be less than 2048 or sum_s16 may overflow.
// Process a block of any size where the width is divisible by 8.
// TODO(johannkoenig): bump this up to 16 at a time.
static void variance_neon_w8(const uint8_t *a, int a_stride, const uint8_t *b,
int b_stride, int w, int h, uint32_t *sse,
int *sum) {
// Process a block of any size where the width is divisible by 16.
static void variance_neon_w16(const uint8_t *a, int a_stride, const uint8_t *b,
int b_stride, int w, int h, uint32_t *sse,
int *sum) {
int i, j;
int16x8_t v_sum = vdupq_n_s16(0);
int32x4_t v_sse_lo = vdupq_n_s32(0);
int32x4_t v_sse_hi = vdupq_n_s32(0);
int16x8_t sum_s16 = vdupq_n_s16(0);
int32x4_t sse_lo_s32 = vdupq_n_s32(0);
int32x4_t sse_hi_s32 = vdupq_n_s32(0);
for (i = 0; i < h; ++i) {
for (j = 0; j < w; j += 8) {
const uint8x8_t v_a = vld1_u8(&a[j]);
const uint8x8_t v_b = vld1_u8(&b[j]);
const uint16x8_t v_diff = vsubl_u8(v_a, v_b);
const int16x8_t sv_diff = vreinterpretq_s16_u16(v_diff);
v_sum = vaddq_s16(v_sum, sv_diff);
v_sse_lo =
vmlal_s16(v_sse_lo, vget_low_s16(sv_diff), vget_low_s16(sv_diff));
v_sse_hi =
vmlal_s16(v_sse_hi, vget_high_s16(sv_diff), vget_high_s16(sv_diff));
for (j = 0; j < w; j += 16) {
const uint8x16_t a_u8 = vld1q_u8(a + j);
const uint8x16_t b_u8 = vld1q_u8(b + j);
const uint16x8_t diff_lo_u16 =
vsubl_u8(vget_low_u8(a_u8), vget_low_u8(b_u8));
const uint16x8_t diff_hi_u16 =
vsubl_u8(vget_high_u8(a_u8), vget_high_u8(b_u8));
const int16x8_t diff_lo_s16 = vreinterpretq_s16_u16(diff_lo_u16);
const int16x8_t diff_hi_s16 = vreinterpretq_s16_u16(diff_hi_u16);
sum_s16 = vaddq_s16(sum_s16, diff_lo_s16);
sum_s16 = vaddq_s16(sum_s16, diff_hi_s16);
sse_lo_s32 = vmlal_s16(sse_lo_s32, vget_low_s16(diff_lo_s16),
vget_low_s16(diff_lo_s16));
sse_lo_s32 = vmlal_s16(sse_lo_s32, vget_high_s16(diff_lo_s16),
vget_high_s16(diff_lo_s16));
sse_hi_s32 = vmlal_s16(sse_hi_s32, vget_low_s16(diff_hi_s16),
vget_low_s16(diff_hi_s16));
sse_hi_s32 = vmlal_s16(sse_hi_s32, vget_high_s16(diff_hi_s16),
vget_high_s16(diff_hi_s16));
}
a += a_stride;
b += b_stride;
}
*sum = horizontal_add_s16x8(v_sum);
*sse = (unsigned int)horizontal_add_s32x4(vaddq_s32(v_sse_lo, v_sse_hi));
*sum = horizontal_add_s16x8(sum_s16);
*sse = (unsigned int)horizontal_add_s32x4(vaddq_s32(sse_lo_s32, sse_hi_s32));
}
// w * h must be less than 2048 or sum_s16 may overflow.
@ -106,7 +119,7 @@ void vpx_get8x8var_neon(const uint8_t *a, int a_stride, const uint8_t *b,
void vpx_get16x16var_neon(const uint8_t *a, int a_stride, const uint8_t *b,
int b_stride, unsigned int *sse, int *sum) {
variance_neon_w8(a, a_stride, b, b_stride, 16, 16, sse, sum);
variance_neon_w16(a, a_stride, b, b_stride, 16, 16, sse, sum);
}
#define varianceNxM(n, m, shift) \
@ -117,7 +130,7 @@ void vpx_get16x16var_neon(const uint8_t *a, int a_stride, const uint8_t *b,
if (n == 8) \
variance_neon_w8x2(a, a_stride, b, b_stride, m, sse, &sum); \
else \
variance_neon_w8(a, a_stride, b, b_stride, n, m, sse, &sum); \
variance_neon_w16(a, a_stride, b, b_stride, n, m, sse, &sum); \
if (n * m < 16 * 16) \
return *sse - ((sum * sum) >> shift); \
else \
@ -138,9 +151,9 @@ unsigned int vpx_variance32x64_neon(const uint8_t *a, int a_stride,
unsigned int *sse) {
int sum1, sum2;
uint32_t sse1, sse2;
variance_neon_w8(a, a_stride, b, b_stride, 32, 32, &sse1, &sum1);
variance_neon_w8(a + (32 * a_stride), a_stride, b + (32 * b_stride), b_stride,
32, 32, &sse2, &sum2);
variance_neon_w16(a, a_stride, b, b_stride, 32, 32, &sse1, &sum1);
variance_neon_w16(a + (32 * a_stride), a_stride, b + (32 * b_stride),
b_stride, 32, 32, &sse2, &sum2);
*sse = sse1 + sse2;
sum1 += sum2;
return *sse - (unsigned int)(((int64_t)sum1 * sum1) >> 11);
@ -151,9 +164,9 @@ unsigned int vpx_variance64x32_neon(const uint8_t *a, int a_stride,
unsigned int *sse) {
int sum1, sum2;
uint32_t sse1, sse2;
variance_neon_w8(a, a_stride, b, b_stride, 64, 16, &sse1, &sum1);
variance_neon_w8(a + (16 * a_stride), a_stride, b + (16 * b_stride), b_stride,
64, 16, &sse2, &sum2);
variance_neon_w16(a, a_stride, b, b_stride, 64, 16, &sse1, &sum1);
variance_neon_w16(a + (16 * a_stride), a_stride, b + (16 * b_stride),
b_stride, 64, 16, &sse2, &sum2);
*sse = sse1 + sse2;
sum1 += sum2;
return *sse - (unsigned int)(((int64_t)sum1 * sum1) >> 11);
@ -165,19 +178,19 @@ unsigned int vpx_variance64x64_neon(const uint8_t *a, int a_stride,
int sum1, sum2;
uint32_t sse1, sse2;
variance_neon_w8(a, a_stride, b, b_stride, 64, 16, &sse1, &sum1);
variance_neon_w8(a + (16 * a_stride), a_stride, b + (16 * b_stride), b_stride,
64, 16, &sse2, &sum2);
variance_neon_w16(a, a_stride, b, b_stride, 64, 16, &sse1, &sum1);
variance_neon_w16(a + (16 * a_stride), a_stride, b + (16 * b_stride),
b_stride, 64, 16, &sse2, &sum2);
sse1 += sse2;
sum1 += sum2;
variance_neon_w8(a + (16 * 2 * a_stride), a_stride, b + (16 * 2 * b_stride),
b_stride, 64, 16, &sse2, &sum2);
variance_neon_w16(a + (16 * 2 * a_stride), a_stride, b + (16 * 2 * b_stride),
b_stride, 64, 16, &sse2, &sum2);
sse1 += sse2;
sum1 += sum2;
variance_neon_w8(a + (16 * 3 * a_stride), a_stride, b + (16 * 3 * b_stride),
b_stride, 64, 16, &sse2, &sum2);
variance_neon_w16(a + (16 * 3 * a_stride), a_stride, b + (16 * 3 * b_stride),
b_stride, 64, 16, &sse2, &sum2);
*sse = sse1 + sse2;
sum1 += sum2;
return *sse - (unsigned int)(((int64_t)sum1 * sum1) >> 12);