From 369781baa423e5d15ab4bd91fa3a0b247c158f12 Mon Sep 17 00:00:00 2001
From: Jonathan Wright <[EMAIL REDACTED]>
Date: Wed, 14 Aug 2024 15:48:01 +0100
Subject: [PATCH] Add Arm Neon USMMLA impl. for 6-tap dist_wtd_convolve_x_avg
Use a USMMLA implementation for the 6-tap and 4-tap basic averaging
case in av1_dist_wtd_convolve_x_neon_i8mm. The rationale is similar to
previous patches adding USMMLA code paths:
By permuting the input samples and the 6-tap filter we can use the
Armv8.6 I8MM USMMLA matrix multiply instructions to accelerate
horizontal 6-tap convolutions. The 2x8 by 8x2 matrix multiply
instruction does twice the work of a USDOT dot product instruction.
We use this new USMMLA 6-tap path for 4-tap filters as well since it
uses exactly the same number of instructions as the previous USDOT
implementation.
Change-Id: Ia3563b57ad320d29df62040472e3eebabf210199
---
av1/common/arm/compound_convolve_neon_i8mm.c | 225 ++++++++++++-------
1 file changed, 140 insertions(+), 85 deletions(-)
diff --git a/av1/common/arm/compound_convolve_neon_i8mm.c b/av1/common/arm/compound_convolve_neon_i8mm.c
index 5b6d0c628..685f13fcc 100644
--- a/av1/common/arm/compound_convolve_neon_i8mm.c
+++ b/av1/common/arm/compound_convolve_neon_i8mm.c
@@ -488,10 +488,47 @@ static inline void dist_wtd_convolve_x_dist_wtd_avg_neon_i8mm(
}
}
-static inline void dist_wtd_convolve_x_avg_neon_i8mm(
- const uint8_t *src, int src_stride, uint8_t *dst8, int dst8_stride, int w,
- int h, const InterpFilterParams *filter_params_x, const int subpel_x_qn,
- ConvolveParams *conv_params) {
+static inline uint16x4_t convolve6_4_x(uint8x16_t samples,
+ const int8x16_t x_filter,
+ const uint8x16_t permute_tbl,
+ const int32x4_t round_offset) {
+ // Permute samples ready for matrix multiply.
+ // { 0, 1, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 8, 9 }
+ uint8x16_t permuted_samples = vqtbl1q_u8(samples, permute_tbl);
+
+ // These instructions multiply a 2x8 matrix (samples) by an 8x2 matrix
+ // (filter), destructively accumulating into the destination register.
+ int32x4_t sum = vusmmlaq_s32(round_offset, permuted_samples, x_filter);
+
+ // We halved the convolution filter values so -1 from the right shift.
+ return vreinterpret_u16_s16(vshrn_n_s32(sum, ROUND0_BITS - 1));
+}
+
+static inline uint16x8_t convolve6_8_x(uint8x16_t samples,
+ const int8x16_t x_filter,
+ const uint8x16x2_t permute_tbl,
+ const int32x4_t round_offset) {
+ // Permute samples ready for matrix multiply.
+ // { 0, 1, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 8, 9 }
+ // { 4, 5, 6, 7, 8, 9, 10, 11, 6, 7, 8, 9, 10, 11, 12, 13 }
+ uint8x16_t permuted_samples[2] = { vqtbl1q_u8(samples, permute_tbl.val[0]),
+ vqtbl1q_u8(samples, permute_tbl.val[1]) };
+
+ // These instructions multiply a 2x8 matrix (samples) by an 8x2 matrix
+ // (filter), destructively accumulating into the destination register.
+ int32x4_t sum0123 = vusmmlaq_s32(round_offset, permuted_samples[0], x_filter);
+ int32x4_t sum4567 = vusmmlaq_s32(round_offset, permuted_samples[1], x_filter);
+
+ // Narrow and re-pack.
+ // We halved the convolution filter values so -1 from the right shift.
+ int16x8_t res = vcombine_s16(vshrn_n_s32(sum0123, ROUND0_BITS - 1),
+ vshrn_n_s32(sum4567, ROUND0_BITS - 1));
+ return vreinterpretq_u16_s16(res);
+}
+
+static inline void dist_wtd_convolve_x_avg_6tap_neon_i8mm(
+ const uint8_t *src, int src_stride, uint16_t *dst, int dst_stride,
+ uint8_t *dst8, int dst8_stride, int w, int h, const int16_t *x_filter_ptr) {
assert(w % 4 == 0);
assert(h % 4 == 0);
@@ -506,63 +543,49 @@ static inline void dist_wtd_convolve_x_avg_neon_i8mm(
const int32x4_t round_offset_shim = vdupq_n_s32(
(round_offset << (ROUND0_BITS - 1)) + (1 << ((ROUND0_BITS - 1) - 1)));
- // Horizontal filter.
- const int16_t *x_filter_ptr = av1_get_interp_filter_subpel_kernel(
- filter_params_x, subpel_x_qn & SUBPEL_MASK);
-
- const int horiz_offset = filter_params_x->taps / 2 - 1;
- const uint8_t *src_ptr = src - horiz_offset;
- CONV_BUF_TYPE *dst_ptr = conv_params->dst;
- uint8_t *dst8_ptr = dst8;
- int dst_stride = conv_params->dst_stride;
- int height = h;
+ // Filter values are even, so halve to reduce intermediate precision reqs.
+ const int8x8_t x_filter_s8 = vshrn_n_s16(vld1q_s16(x_filter_ptr), 1);
+ // Stagger the filter for use with the matrix multiply instructions.
+ // { f0, f1, f2, f3, f4, f5, 0, 0, 0, f0, f1, f2, f3, f4, f5, 0 }
+ const int8x16_t x_filter =
+ vcombine_s8(vext_s8(x_filter_s8, x_filter_s8, 1), x_filter_s8);
if (w == 4) {
- const uint8x16_t permute_tbl = vld1q_u8(kDotProdPermuteTbl);
- // 4-tap filters are used for blocks having width <= 4.
- // Filter values are even, so halve to reduce intermediate precision reqs.
- const int8x8_t x_filter =
- vshrn_n_s16(vcombine_s16(vld1_s16(x_filter_ptr + 2), vdup_n_s16(0)), 1);
-
- src_ptr += 2;
-
+ const uint8x16_t permute_tbl = vld1q_u8(kMatMulPermuteTbl);
do {
uint8x16_t s0, s1, s2, s3;
- load_u8_16x4(src_ptr, src_stride, &s0, &s1, &s2, &s3);
+ load_u8_16x4(src, src_stride, &s0, &s1, &s2, &s3);
uint16x4_t d0 =
- convolve4_4_x(s0, x_filter, permute_tbl, round_offset_shim);
+ convolve6_4_x(s0, x_filter, permute_tbl, round_offset_shim);
uint16x4_t d1 =
- convolve4_4_x(s1, x_filter, permute_tbl, round_offset_shim);
+ convolve6_4_x(s1, x_filter, permute_tbl, round_offset_shim);
uint16x4_t d2 =
- convolve4_4_x(s2, x_filter, permute_tbl, round_offset_shim);
+ convolve6_4_x(s2, x_filter, permute_tbl, round_offset_shim);
uint16x4_t d3 =
- convolve4_4_x(s3, x_filter, permute_tbl, round_offset_shim);
+ convolve6_4_x(s3, x_filter, permute_tbl, round_offset_shim);
uint16x4_t dd0, dd1, dd2, dd3;
- load_u16_4x4(dst_ptr, dst_stride, &dd0, &dd1, &dd2, &dd3);
+ load_u16_4x4(dst, dst_stride, &dd0, &dd1, &dd2, &dd3);
uint8x8_t d01_u8, d23_u8;
compute_basic_avg_4x4(dd0, dd1, dd2, dd3, d0, d1, d2, d3,
round_offset_vec, &d01_u8, &d23_u8);
- store_u8x4_strided_x2(dst8_ptr + 0 * dst8_stride, dst8_stride, d01_u8);
- store_u8x4_strided_x2(dst8_ptr + 2 * dst8_stride, dst8_stride, d23_u8);
+ store_u8x4_strided_x2(dst8 + 0 * dst8_stride, dst8_stride, d01_u8);
+ store_u8x4_strided_x2(dst8 + 2 * dst8_stride, dst8_stride, d23_u8);
- src_ptr += 4 * src_stride;
- dst_ptr += 4 * dst_stride;
- dst8_ptr += 4 * dst8_stride;
- height -= 4;
- } while (height != 0);
+ src += 4 * src_stride;
+ dst += 4 * dst_stride;
+ dst8 += 4 * dst8_stride;
+ h -= 4;
+ } while (h != 0);
} else {
- const uint8x16x3_t permute_tbl = vld1q_u8_x3(kDotProdPermuteTbl);
- // Filter values are even, so halve to reduce intermediate precision reqs.
- const int8x8_t x_filter = vshrn_n_s16(vld1q_s16(x_filter_ptr), 1);
-
+ const uint8x16x2_t permute_tbl = vld1q_u8_x2(kMatMulPermuteTbl);
do {
- const uint8_t *s = src_ptr;
- CONV_BUF_TYPE *d = dst_ptr;
- uint8_t *d_u8 = dst8_ptr;
+ const uint8_t *s = src;
+ uint16_t *d = dst;
+ uint8_t *d_u8 = dst8;
int width = w;
do {
@@ -570,13 +593,13 @@ static inline void dist_wtd_convolve_x_avg_neon_i8mm(
load_u8_16x4(s, src_stride, &s0, &s1, &s2, &s3);
uint16x8_t d0 =
- convolve8_8_x(s0, x_filter, permute_tbl, round_offset_shim);
+ convolve6_8_x(s0, x_filter, permute_tbl, round_offset_shim);
uint16x8_t d1 =
- convolve8_8_x(s1, x_filter, permute_tbl, round_offset_shim);
+ convolve6_8_x(s1, x_filter, permute_tbl, round_offset_shim);
uint16x8_t d2 =
- convolve8_8_x(s2, x_filter, permute_tbl, round_offset_shim);
+ convolve6_8_x(s2, x_filter, permute_tbl, round_offset_shim);
uint16x8_t d3 =
- convolve8_8_x(s3, x_filter, permute_tbl, round_offset_shim);
+ convolve6_8_x(s3, x_filter, permute_tbl, round_offset_shim);
uint16x8_t dd0, dd1, dd2, dd3;
load_u16_8x4(d, dst_stride, &dd0, &dd1, &dd2, &dd3);
@@ -592,50 +615,73 @@ static inline void dist_wtd_convolve_x_avg_neon_i8mm(
d_u8 += 8;
width -= 8;
} while (width != 0);
- src_ptr += 4 * src_stride;
- dst_ptr += 4 * dst_stride;
- dst8_ptr += 4 * dst8_stride;
- height -= 4;
- } while (height != 0);
+ src += 4 * src_stride;
+ dst += 4 * dst_stride;
+ dst8 += 4 * dst8_stride;
+ h -= 4;
+ } while (h != 0);
}
}
-static inline uint16x4_t convolve6_4_x(uint8x16_t samples,
- const int8x16_t x_filter,
- const uint8x16_t permute_tbl,
- const int32x4_t round_offset) {
- // Permute samples ready for matrix multiply.
- // { 0, 1, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 8, 9 }
- uint8x16_t permuted_samples = vqtbl1q_u8(samples, permute_tbl);
+static inline void dist_wtd_convolve_x_avg_8tap_neon_i8mm(
+ const uint8_t *src, int src_stride, uint16_t *dst, int dst_stride,
+ uint8_t *dst8, int dst8_stride, int w, int h, const int16_t *x_filter_ptr) {
+ assert(w % 4 == 0);
+ assert(h % 4 == 0);
- // These instructions multiply a 2x8 matrix (samples) by an 8x2 matrix
- // (filter), destructively accumulating into the destination register.
- int32x4_t sum = vusmmlaq_s32(round_offset, permuted_samples, x_filter);
+ const int bd = 8;
+ const int offset_bits = bd + 2 * FILTER_BITS - ROUND0_BITS;
+ const int16_t round_offset = (1 << (offset_bits - COMPOUND_ROUND1_BITS)) +
+ (1 << (offset_bits - COMPOUND_ROUND1_BITS - 1));
+ const int16x8_t round_offset_vec = vdupq_n_s16(round_offset);
+ // A shim of 1 << ((ROUND0_BITS - 1) - 1) enables us to use non-rounding
+ // shifts - which are generally faster than rounding shifts on modern CPUs.
+ // (The extra -1 is needed because we halved the filter values.)
+ const int32x4_t round_offset_shim = vdupq_n_s32(
+ (round_offset << (ROUND0_BITS - 1)) + (1 << ((ROUND0_BITS - 1) - 1)));
- // We halved the convolution filter values so -1 from the right shift.
- return vreinterpret_u16_s16(vshrn_n_s32(sum, ROUND0_BITS - 1));
-}
+ const uint8x16x3_t permute_tbl = vld1q_u8_x3(kDotProdPermuteTbl);
+ // Filter values are even, so halve to reduce intermediate precision reqs.
+ const int8x8_t x_filter = vshrn_n_s16(vld1q_s16(x_filter_ptr), 1);
-static inline uint16x8_t convolve6_8_x(uint8x16_t samples,
- const int8x16_t x_filter,
- const uint8x16x2_t permute_tbl,
- const int32x4_t round_offset) {
- // Permute samples ready for matrix multiply.
- // { 0, 1, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 8, 9 }
- // { 4, 5, 6, 7, 8, 9, 10, 11, 6, 7, 8, 9, 10, 11, 12, 13 }
- uint8x16_t permuted_samples[2] = { vqtbl1q_u8(samples, permute_tbl.val[0]),
- vqtbl1q_u8(samples, permute_tbl.val[1]) };
+ do {
+ const uint8_t *s = src;
+ uint16_t *d = dst;
+ uint8_t *d_u8 = dst8;
+ int width = w;
- // These instructions multiply a 2x8 matrix (samples) by an 8x2 matrix
- // (filter), destructively accumulating into the destination register.
- int32x4_t sum0123 = vusmmlaq_s32(round_offset, permuted_samples[0], x_filter);
- int32x4_t sum4567 = vusmmlaq_s32(round_offset, permuted_samples[1], x_filter);
+ do {
+ uint8x16_t s0, s1, s2, s3;
+ load_u8_16x4(s, src_stride, &s0, &s1, &s2, &s3);
- // Narrow and re-pack.
- // We halved the convolution filter values so -1 from the right shift.
- int16x8_t res = vcombine_s16(vshrn_n_s32(sum0123, ROUND0_BITS - 1),
- vshrn_n_s32(sum4567, ROUND0_BITS - 1));
- return vreinterpretq_u16_s16(res);
+ uint16x8_t d0 =
+ convolve8_8_x(s0, x_filter, permute_tbl, round_offset_shim);
+ uint16x8_t d1 =
+ convolve8_8_x(s1, x_filter, permute_tbl, round_offset_shim);
+ uint16x8_t d2 =
+ convolve8_8_x(s2, x_filter, permute_tbl, round_offset_shim);
+ uint16x8_t d3 =
+ convolve8_8_x(s3, x_filter, permute_tbl, round_offset_shim);
+
+ uint16x8_t dd0, dd1, dd2, dd3;
+ load_u16_8x4(d, dst_stride, &dd0, &dd1, &dd2, &dd3);
+
+ uint8x8_t d0_u8, d1_u8, d2_u8, d3_u8;
+ compute_basic_avg_8x4(dd0, dd1, dd2, dd3, d0, d1, d2, d3,
+ round_offset_vec, &d0_u8, &d1_u8, &d2_u8, &d3_u8);
+
+ store_u8_8x4(d_u8, dst8_stride, d0_u8, d1_u8, d2_u8, d3_u8);
+
+ s += 8;
+ d += 8;
+ d_u8 += 8;
+ width -= 8;
+ } while (width != 0);
+ src += 4 * src_stride;
+ dst += 4 * dst_stride;
+ dst8 += 4 * dst8_stride;
+ h -= 4;
+ } while (h != 0);
}
static inline void dist_wtd_convolve_x_6tap_neon_i8mm(
@@ -780,9 +826,18 @@ void av1_dist_wtd_convolve_x_neon_i8mm(
src, src_stride, dst8, dst8_stride, w, h, filter_params_x,
subpel_x_qn, conv_params);
} else {
- dist_wtd_convolve_x_avg_neon_i8mm(src, src_stride, dst8, dst8_stride, w,
- h, filter_params_x, subpel_x_qn,
- conv_params);
+ src -= (SUBPEL_TAPS / 2 - 1);
+
+ if (filter_taps < 8) {
+ dist_wtd_convolve_x_avg_6tap_neon_i8mm(
+ src + 1, src_stride, conv_params->dst, conv_params->dst_stride,
+ dst8, dst8_stride, w, h, x_filter_ptr);
+ return;
+ }
+
+ dist_wtd_convolve_x_avg_8tap_neon_i8mm(src, src_stride, conv_params->dst,
+ conv_params->dst_stride, dst8,
+ dst8_stride, w, h, x_filter_ptr);
}
} else {
src -= (SUBPEL_TAPS / 2 - 1);