opencv/modules/imgproc/src/sumpixels.avx512_skx.hpp
2020-01-17 16:54:29 +03:00

468 lines
21 KiB
C++

// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html.
//
// Copyright (C) 2019-2020, Intel Corporation, all rights reserved.
#include "opencv2/core/hal/intrin.hpp"
namespace cv { namespace hal {
CV_CPU_OPTIMIZATION_NAMESPACE_BEGIN
namespace { // Anonymous namespace to avoid exposing the implementation classes
//
// NOTE: Look at the bottom of the file for the entry-point function for external callers
//
template<size_t num_channels> class IntegralCalculator;
template<size_t num_channels>
class IntegralCalculator {
public:
IntegralCalculator() {};
void calculate_integral_avx512(const uchar *src, size_t _srcstep,
double *sum, size_t _sumstep,
double *sqsum, size_t _sqsumstep,
int width, int height)
{
const int srcstep = (int)(_srcstep/sizeof(uchar));
const int sumstep = (int)(_sumstep/sizeof(double));
const int sqsumstep = (int)(_sqsumstep/sizeof(double));
const int ops_per_line = width * num_channels;
// Clear the first line of the sum as per spec (see integral documentation)
// Also adjust the index of sum and sqsum to be at the real 0th element
// and not point to the border pixel so it stays in sync with the src pointer
memset( sum, 0, (ops_per_line+num_channels)*sizeof(double));
sum += num_channels;
if (sqsum) {
memset( sqsum, 0, (ops_per_line+num_channels)*sizeof(double));
sqsum += num_channels;
}
// Now calculate the integral over the whole image one line at a time
for(int y = 0; y < height; y++) {
const uchar * src_line = &src[y*srcstep];
double * sum_above = &sum[y*sumstep];
double * sum_line = &sum_above[sumstep];
double * sqsum_above = (sqsum) ? &sqsum[y*sqsumstep] : NULL;
double * sqsum_line = (sqsum) ? &sqsum_above[sqsumstep] : NULL;
calculate_integral_for_line(src_line, sum_line, sum_above, sqsum_line, sqsum_above, ops_per_line);
}
}
static CV_ALWAYS_INLINE
void calculate_integral_for_line(const uchar *srcs,
double *sums, double *sums_above,
double *sqsums, double *sqsums_above,
int num_ops_in_line)
{
__m512i sum_accumulator = _mm512_setzero_si512(); // holds rolling sums for the line
__m512i sqsum_accumulator = _mm512_setzero_si512(); // holds rolling sqsums for the line
// The first element on each line must be zeroes as per spec (see integral documentation)
zero_out_border_pixel(sums, sqsums);
// Do all 64 byte chunk operations then do the last bits that don't fit in a 64 byte chunk
aligned_integral( srcs, sums, sums_above, sqsums, sqsums_above, sum_accumulator, sqsum_accumulator, num_ops_in_line);
post_aligned_integral(srcs, sums, sums_above, sqsums, sqsums_above, sum_accumulator, sqsum_accumulator, num_ops_in_line);
}
static CV_ALWAYS_INLINE
void zero_out_border_pixel(double *sums, double *sqsums)
{
// Note the negative index is because the sums/sqsums pointers point to the first real pixel
// after the border pixel so we have to look backwards
_mm512_mask_storeu_epi64(&sums[-(ptrdiff_t)num_channels], (1<<num_channels)-1, _mm512_setzero_si512());
if (sqsums)
_mm512_mask_storeu_epi64(&sqsums[-(ptrdiff_t)num_channels], (1<<num_channels)-1, _mm512_setzero_si512());
}
static CV_ALWAYS_INLINE
void aligned_integral(const uchar *&srcs,
double *&sums, double *&sums_above,
double *&sqsum, double *&sqsum_above,
__m512i &sum_accumulator, __m512i &sqsum_accumulator,
int num_ops_in_line)
{
// This function handles full 64 byte chunks of the source data at a time until it gets to the part of
// the line that no longer contains a full 64 byte chunk. Other code will handle the last part.
const int num_chunks = num_ops_in_line >> 6; // quick int divide by 64
for (int index_64byte_chunk = 0; index_64byte_chunk < num_chunks; index_64byte_chunk++){
integral_64_operations_avx512((__m512i *) srcs,
(__m512i *) sums, (__m512i *) sums_above,
(__m512i *) sqsum, (__m512i *) sqsum_above,
0xFFFFFFFFFFFFFFFF, sum_accumulator, sqsum_accumulator);
srcs+=64; sums+=64; sums_above+=64;
if (sqsum){ sqsum+= 64; sqsum_above+=64; }
}
}
static CV_ALWAYS_INLINE
void post_aligned_integral(const uchar *srcs,
const double *sums, const double *sums_above,
const double *sqsum, const double *sqsum_above,
__m512i &sum_accumulator, __m512i &sqsum_accumulator,
int num_ops_in_line)
{
// This function handles the last few straggling operations that are not a full chunk of 64 operations
// We use the same algorithm, but we calculate a different operation mask using (num_ops % 64).
const unsigned int num_operations = (unsigned int) num_ops_in_line & 0x3F; // Quick int modulo 64
if (num_operations > 0) {
__mmask64 operation_mask = (1ULL << num_operations) - 1ULL;
integral_64_operations_avx512((__m512i *) srcs, (__m512i *) sums, (__m512i *) sums_above,
(__m512i *) sqsum, (__m512i *) sqsum_above,
operation_mask, sum_accumulator, sqsum_accumulator);
}
}
static CV_ALWAYS_INLINE
void integral_64_operations_avx512(const __m512i *srcs,
__m512i *sums, const __m512i *sums_above,
__m512i *sqsums, const __m512i *sqsums_above,
__mmask64 data_mask,
__m512i &sum_accumulator, __m512i &sqsum_accumulator)
{
__m512i src_64byte_chunk = read_64_bytes(srcs, data_mask);
while (data_mask) {
__m128i src_16bytes = extract_lower_16bytes(src_64byte_chunk);
__m512i src_longs_lo = convert_lower_8bytes_to_longs(src_16bytes);
__m512i src_longs_hi = convert_lower_8bytes_to_longs(shift_right_8_bytes(src_16bytes));
// Calculate integral for the sum on the 8 lanes at a time
integral_8_operations(src_longs_lo, sums_above, data_mask, sums, sum_accumulator);
integral_8_operations(src_longs_hi, sums_above+1, data_mask>>8, sums+1, sum_accumulator);
if (sqsums) {
__m512i squared_source_lo = square_m512(src_longs_lo);
__m512i squared_source_hi = square_m512(src_longs_hi);
integral_8_operations(squared_source_lo, sqsums_above, data_mask, sqsums, sqsum_accumulator);
integral_8_operations(squared_source_hi, sqsums_above+1, data_mask>>8, sqsums+1, sqsum_accumulator);
sqsums += 2;
sqsums_above+=2;
}
// Prepare for next iteration of loop
// shift source to align next 16 bytes to lane 0, shift the mask, and advance the pointers
sums += 2;
sums_above += 2;
data_mask = data_mask >> 16;
src_64byte_chunk = shift_right_16_bytes(src_64byte_chunk);
}
}
static CV_ALWAYS_INLINE
void integral_8_operations(const __m512i src_longs, const __m512i *above_values_ptr, __mmask64 data_mask,
__m512i *results_ptr, __m512i &accumulator)
{
// NOTE that the calculate_integral function referenced here must be implemented in the templated
// derivatives because the algorithm depends heavily on the number of channels in the image
//
_mm512_mask_storeu_pd(
results_ptr, // Store the result here
(__mmask8)data_mask, // Using the data mask to avoid overrunning the line
calculate_integral( // Writing the value of the integral derived from:
src_longs, // input data
_mm512_maskz_loadu_pd((__mmask8)data_mask, above_values_ptr), // and the results from line above
accumulator // keeping track of the accumulator
)
);
}
static CV_ALWAYS_INLINE
__m512i read_64_bytes(const __m512i *srcs, const __mmask64 data_mask) {
return _mm512_maskz_loadu_epi8(data_mask, srcs);
}
static CV_ALWAYS_INLINE
__m128i extract_lower_16bytes(const __m512i src_64byte_chunk) {
return _mm512_extracti64x2_epi64(src_64byte_chunk, 0x0);
}
static CV_ALWAYS_INLINE
__m512i convert_lower_8bytes_to_longs(const __m128i src_16bytes) {
return _mm512_cvtepu8_epi64(src_16bytes);
}
static CV_ALWAYS_INLINE
__m512i square_m512(const __m512i src_longs) {
return _mm512_mullo_epi64(src_longs, src_longs);
}
static CV_ALWAYS_INLINE
__m128i shift_right_8_bytes(const __m128i src_16bytes) {
return _mm_maskz_compress_epi64(2, src_16bytes);
}
static CV_ALWAYS_INLINE
__m512i shift_right_16_bytes(const __m512i src_64byte_chunk) {
return _mm512_maskz_compress_epi64(0xFC, src_64byte_chunk);
}
static CV_ALWAYS_INLINE
__m512i m512_hadd(const __m512i a){
return _mm512_add_epi64(_mm512_maskz_compress_epi64(0xAA, a), _mm512_maskz_compress_epi64(0x55, a));
}
// The calculate_integral function referenced here must be implemented in the templated derivatives
// because the algorithm depends heavily on the number of channels in the image
// This is the incomplete definition (just the prototype) here.
//
static CV_ALWAYS_INLINE
__m512d calculate_integral(const __m512i src_longs, const __m512d above_values, __m512i &accumulator);
};
//============================================================================================================
// This the only section that needs to change with respect to algorithm based on the number of channels
// It is responsible for returning the calculation of 8 lanes worth of the integral and returning in the
// accumulated sums in the accumulator parameter (NOTE: accumulator is an input and output parameter)
//
// The function prototype that needs to be implemented is:
//
// __m512d calculate_integral(const __m512i src_longs, const __m512d above_values, __m512i &accumulator){ ... }
//
// Description of parameters:
// INPUTS:
// src_longs : 8 lanes worth of the source bytes converted to 64 bit integers
// above_values: 8 lanes worth of the result values from the line above (See the integral spec)
// accumulator : 8 lanes worth of sums from the previous iteration
// IMPORTANT NOTE: This parameter is both an INPUT AND OUTPUT parameter to this function
//
// OUTPUTS:
// return value: The actual integral value for all 8 lanes which is defined by the spec as
// the sum of all channel values to the left of a given pixel plus the result
// written to the line directly above the current line.
// accumulator: This is an input and and output. This parameter should be left with the accumulated
// sums for the current 8 lanes keeping all entries in the proper lane (do not shuffle it)
//
// Below here is the channel specific implementation
//
//========================================
// 1 Channel Integral Implementation
//========================================
template<>
CV_ALWAYS_INLINE
__m512d IntegralCalculator < 1 > ::calculate_integral(const __m512i src_longs, const __m512d above_values, __m512i &accumulator)
{
// One channel support is implemented differently than 2, 3, or 4 channel
// One channel support has more horizontal operations that cannot be made vertical without losing performance
// The logical operations needed look like:
// Vertical LANES : |7|6|5|4|3|2|1|0|
// src_longs : |H|G|F|E|D|C|B|A|
// shift_by_1 : + |G|F|E|D|C|B|A| |
// shift_by_2 : + |F|E|D|C|B|A| | |
// shift_by_3 : + |E|D|C|B|A| | | |
// shift_by_4 : + |D|C|B|A| | | | |
// shift_by_5 : + |C|B|A| | | | | |
// shift_by_6 : + |B|A| | | | | | |
// shift_by_7 : + |A| | | | | | | |
// carry_over_idxs : + |7|7|7|7|7|7|7|7| (index position of result from previous iteration)
// = integral
//
// If we do this vertically we end up losing performance because of the number of operations. We will instead
// do a horizontal add tree to create the vertical sections we need as a tree
// Vertical Lanes: | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
// src_longs: | H | G | F | E | D | C | B | A |
// horiz_sum_1: | | | | | G+H | E+F | C+D | A+B |
// horiz_sum_2: | | | | | | | EFGH | ABCD |
//
const __m512i horiz_sum_1 = m512_hadd(src_longs); // indexes for the permutes below (3,2,1,0) = (GH, EF, CD, AB)
const __m512i horiz_sum_2 = m512_hadd(horiz_sum_1); // indexes for the permutes below (9, 8) = (EFGH, ABCD)
// Then we can use the partial sums by looking at the vertical stacks above and realize that, for example
// ABCD appears vertically in lanes 7, 6, 5, 4, and 3 so we will permute the values so that all partial products
// appear in the right lanes. and sum them up along with the carry over value from the accumulator. So we setup
// the lanes like:
// Vertical Lanes: | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
// s1 : | 0 | G | 0 | E | 0 | C | 0 | A |
// s2 : | ABCD | ABCD | ABCD | ABCD | ABCD | AB | AB | 0 |
// s3 : | EFGH | EF | EF | 0 | 0 | 0 | 0 | 0 |
// +------+------+------+------+------+------+------+------+
// sum : | A..H | A..G | A..F | A..E | A..D | A..C | A..B | A | Integral :-)
//
const __m512i s1 = _mm512_maskz_mov_epi64(0x55, src_longs); // 0 G 0 E 0 D 0 C 0 A
const __m512i s2 = _mm512_permutex2var_epi64(horiz_sum_1, _mm512_set_epi64(8,8,8,8,8,0,0,4), horiz_sum_2);
const __m512i s3 = _mm512_permutex2var_epi64(horiz_sum_1, _mm512_set_epi64(9,2,2,4,4,4,4,4), horiz_sum_2);
// Now we use the rolling sum from the previous iteration from accumulator and replicate it into carry_over
// And sum everything up into the accumulator
//
const __m512i carry_over = _mm512_permutex2var_epi64(accumulator, _mm512_set_epi64(7,7,7,7,7,7,7,7), accumulator);
accumulator = _mm512_add_epi64(_mm512_add_epi64(s2, s3), _mm512_add_epi64(carry_over, s1));
// Convert to double precision and store
//
__m512d integral_pd = _mm512_add_pd(_mm512_cvtepu64_pd(accumulator), above_values);
return integral_pd;
}
//========================================
// 2 Channel Integral Implementation
//========================================
template<>
CV_ALWAYS_INLINE
__m512d IntegralCalculator < 2 > ::calculate_integral(const __m512i src_longs, const __m512d above_values, __m512i &accumulator)
{
__m512i carryover_idxs = _mm512_set_epi64(7, 6, 7, 6, 7, 6, 7, 6);
// Align data to prepare for the adds:
// shifts data left by 3 and 6 qwords(lanes) and gets rolling sum in all lanes
// Vertical LANES : 76543210
// src_longs : HGFEDCBA
// shift2lanes : + FEDCBA
// shift4lanes : + DCBA
// shift6lanes : + BA
// carry_over_idxs : + 76767676 (index position of result from previous iteration)
// = integral
__m512i shift2lanes = _mm512_maskz_expand_epi64(0xFC, src_longs);
__m512i shift4lanes = _mm512_maskz_expand_epi64(0xF0, src_longs);
__m512i shift6lanes = _mm512_maskz_expand_epi64(0xC0, src_longs);
__m512i carry_over = _mm512_permutex2var_epi64(accumulator, carryover_idxs, accumulator);
// Add all values in tree form for perf ((0+2) + (4+6))
__m512i sum_shift_02 = _mm512_add_epi64(src_longs, shift2lanes);
__m512i sum_shift_46 = _mm512_add_epi64(shift4lanes, shift6lanes);
__m512i sum_all = _mm512_add_epi64(sum_shift_02, sum_shift_46);
accumulator = _mm512_add_epi64(sum_all, carry_over);
// Convert to packed double and add to the line above to get the true integral value
__m512d accumulator_pd = _mm512_cvtepu64_pd(accumulator);
__m512d integral_pd = _mm512_add_pd(accumulator_pd, above_values);
return integral_pd;
}
//========================================
// 3 Channel Integral Implementation
//========================================
template<>
CV_ALWAYS_INLINE
__m512d IntegralCalculator < 3 > ::calculate_integral(const __m512i src_longs, const __m512d above_values, __m512i &accumulator)
{
__m512i carryover_idxs = _mm512_set_epi64(6, 5, 7, 6, 5, 7, 6, 5);
// Align data to prepare for the adds:
// shifts data left by 3 and 6 qwords(lanes) and gets rolling sum in all lanes
// Vertical LANES: 76543210
// src_longs : HGFEDCBA
// shit3lanes : + EDCBA
// shift6lanes : + BA
// carry_over_idxs : + 65765765 (index position of result from previous iteration)
// = integral
__m512i shift3lanes = _mm512_maskz_expand_epi64(0xF8, src_longs);
__m512i shift6lanes = _mm512_maskz_expand_epi64(0xC0, src_longs);
__m512i carry_over = _mm512_permutex2var_epi64(accumulator, carryover_idxs, accumulator);
// Do the adds in tree form
__m512i sum_shift_03 = _mm512_add_epi64(src_longs, shift3lanes);
__m512i sum_rest = _mm512_add_epi64(shift6lanes, carry_over);
accumulator = _mm512_add_epi64(sum_shift_03, sum_rest);
// Convert to packed double and add to the line above to get the true integral value
__m512d accumulator_pd = _mm512_cvtepu64_pd(accumulator);
__m512d integral_pd = _mm512_add_pd(accumulator_pd, above_values);
return integral_pd;
}
//========================================
// 4 Channel Integral Implementation
//========================================
template<>
CV_ALWAYS_INLINE
__m512d IntegralCalculator < 4 > ::calculate_integral(const __m512i src_longs, const __m512d above_values, __m512i &accumulator)
{
__m512i carryover_idxs = _mm512_set_epi64(7, 6, 5, 4, 7, 6, 5, 4);
// Align data to prepare for the adds:
// shifts data left by 3 and 6 qwords(lanes) and gets rolling sum in all lanes
// Vertical LANES: 76543210
// src_longs : HGFEDCBA
// shit4lanes : + DCBA
// carry_over_idxs : + 76547654 (index position of result from previous iteration)
// = integral
__m512i shifted4lanes = _mm512_maskz_expand_epi64(0xF0, src_longs);
__m512i carry_over = _mm512_permutex2var_epi64(accumulator, carryover_idxs, accumulator);
// Add data pixels and carry over from last iteration
__m512i sum_shift_04 = _mm512_add_epi64(src_longs, shifted4lanes);
accumulator = _mm512_add_epi64(sum_shift_04, carry_over);
// Convert to packed double and add to the line above to get the true integral value
__m512d accumulator_pd = _mm512_cvtepu64_pd(accumulator);
__m512d integral_pd = _mm512_add_pd(accumulator_pd, above_values);
return integral_pd;
}
} // end of anonymous namespace
static
void calculate_integral_avx512(const uchar *src, size_t _srcstep,
double *sum, size_t _sumstep,
double *sqsum, size_t _sqsumstep,
int width, int height, int cn)
{
CV_INSTRUMENT_REGION();
switch(cn){
case 1: {
IntegralCalculator< 1 > calculator;
calculator.calculate_integral_avx512(src, _srcstep, sum, _sumstep, sqsum, _sqsumstep, width, height);
break;
}
case 2: {
IntegralCalculator< 2 > calculator;
calculator.calculate_integral_avx512(src, _srcstep, sum, _sumstep, sqsum, _sqsumstep, width, height);
break;
}
case 3: {
IntegralCalculator< 3 > calculator;
calculator.calculate_integral_avx512(src, _srcstep, sum, _sumstep, sqsum, _sqsumstep, width, height);
break;
}
case 4: {
IntegralCalculator< 4 > calculator;
calculator.calculate_integral_avx512(src, _srcstep, sum, _sumstep, sqsum, _sqsumstep, width, height);
}
}
}
CV_CPU_OPTIMIZATION_NAMESPACE_END
}} // end namespace cv::hal