tesseract/src/arch/simddetect.cpp
Brad Smith 3157ff0e74
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Fix building elf_aux_info() support on OpenBSD/arm
Remove the unnecessary use of the sys/elf.h header which breaks
the build.
2025-01-17 11:55:52 +01:00

375 lines
12 KiB
C++

///////////////////////////////////////////////////////////////////////
// File: simddetect.cpp
// Description: Architecture detector.
// Author: Stefan Weil (based on code from Ray Smith)
//
// (C) Copyright 2014, Google Inc.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
///////////////////////////////////////////////////////////////////////
#ifdef HAVE_CONFIG_H
# include "config_auto.h" // for HAVE_AVX, ...
#endif
#include <numeric> // for std::inner_product
#include "dotproduct.h"
#include "intsimdmatrix.h" // for IntSimdMatrix
#include "params.h" // for STRING_VAR
#include "simddetect.h"
#include "tprintf.h" // for tprintf
#if !defined(__clang__) && defined(__GNUC__) && (__GNUC__ < 12)
// The GNU compiler g++ fails to compile with the Accelerate framework
// (tested with versions 10 and 11), so unconditionally disable it.
#undef HAVE_FRAMEWORK_ACCELERATE
#endif
#if defined(HAVE_FRAMEWORK_ACCELERATE)
// Use Apple Accelerate framework.
// https://developer.apple.com/documentation/accelerate/simd
#include <Accelerate/Accelerate.h>
#endif
#if defined(HAVE_AVX) || defined(HAVE_AVX2) || defined(HAVE_FMA) || defined(HAVE_SSE4_1)
// See https://en.wikipedia.org/wiki/CPUID.
# define HAS_CPUID
#endif
#if defined(HAS_CPUID)
# if defined(__GNUC__)
# include <cpuid.h>
# elif defined(_WIN32)
# include <intrin.h>
# endif
#endif
#if defined(HAVE_NEON) && !defined(__aarch64__)
# if defined(HAVE_ANDROID_GETCPUFAMILY)
# include <cpu-features.h>
# elif defined(HAVE_GETAUXVAL)
# include <asm/hwcap.h>
# include <sys/auxv.h>
# elif defined(HAVE_ELF_AUX_INFO)
# include <sys/auxv.h>
# endif
#endif
#if defined(HAVE_RVV)
# if defined(HAVE_GETAUXVAL) || defined(HAVE_ELF_AUX_INFO)
# include <sys/auxv.h>
# define HWCAP_RV(letter) (1ul << ((letter) - 'A'))
# endif
#endif
namespace tesseract {
// Computes and returns the dot product of the two n-vectors u and v.
// Note: because the order of addition is different among the different dot
// product functions, the results can (and do) vary slightly (although they
// agree to within about 4e-15). This produces different results when running
// training, despite all random inputs being precisely equal.
// To get consistent results, use just one of these dot product functions.
// On a test multi-layer network, serial is 57% slower than SSE, and AVX
// is about 8% faster than SSE. This suggests that the time is memory
// bandwidth constrained and could benefit from holding the reused vector
// in AVX registers.
DotProductFunction DotProduct;
static STRING_VAR(dotproduct, "auto", "Function used for calculation of dot product");
SIMDDetect SIMDDetect::detector;
#if defined(__aarch64__)
// ARMv8 always has NEON.
bool SIMDDetect::neon_available_ = true;
#elif defined(HAVE_NEON)
// If true, then Neon has been detected.
bool SIMDDetect::neon_available_;
#elif defined(HAVE_RVV)
bool SIMDDetect::rvv_available_;
#else
// If true, then AVX has been detected.
bool SIMDDetect::avx_available_;
bool SIMDDetect::avx2_available_;
bool SIMDDetect::avx512F_available_;
bool SIMDDetect::avx512BW_available_;
bool SIMDDetect::avx512VNNI_available_;
// If true, then FMA has been detected.
bool SIMDDetect::fma_available_;
// If true, then SSe4.1 has been detected.
bool SIMDDetect::sse_available_;
#endif
#if defined(HAVE_FRAMEWORK_ACCELERATE)
static TFloat DotProductAccelerate(const TFloat* u, const TFloat* v, int n) {
TFloat total = 0;
const int stride = 1;
#if defined(FAST_FLOAT)
vDSP_dotpr(u, stride, v, stride, &total, n);
#else
vDSP_dotprD(u, stride, v, stride, &total, n);
#endif
return total;
}
#endif
// Computes and returns the dot product of the two n-vectors u and v.
static TFloat DotProductGeneric(const TFloat *u, const TFloat *v, int n) {
TFloat total = 0;
for (int k = 0; k < n; ++k) {
total += u[k] * v[k];
}
return total;
}
// Compute dot product using std::inner_product.
static TFloat DotProductStdInnerProduct(const TFloat *u, const TFloat *v, int n) {
return std::inner_product(u, u + n, v, static_cast<TFloat>(0));
}
static void SetDotProduct(DotProductFunction f, const IntSimdMatrix *m = nullptr) {
DotProduct = f;
IntSimdMatrix::intSimdMatrix = m;
}
// Constructor.
// Tests the architecture in a system-dependent way to detect AVX, SSE and
// any other available SIMD equipment.
// __GNUC__ is also defined by compilers that include GNU extensions such as
// clang.
SIMDDetect::SIMDDetect() {
// The fallback is a generic dot product calculation.
SetDotProduct(DotProductGeneric);
#if defined(HAS_CPUID)
# if defined(__GNUC__)
unsigned int eax, ebx, ecx, edx;
if (__get_cpuid(1, &eax, &ebx, &ecx, &edx) != 0) {
// Note that these tests all use hex because the older compilers don't have
// the newer flags.
# if defined(HAVE_SSE4_1)
sse_available_ = (ecx & 0x00080000) != 0;
# endif
# if defined(HAVE_AVX) || defined(HAVE_AVX2) || defined(HAVE_FMA)
auto xgetbv = []() {
uint32_t xcr0;
__asm__("xgetbv" : "=a"(xcr0) : "c"(0) : "%edx");
return xcr0;
};
if ((ecx & 0x08000000) && ((xgetbv() & 6) == 6)) {
// OSXSAVE bit is set, XMM state and YMM state are fine.
# if defined(HAVE_FMA)
fma_available_ = (ecx & 0x00001000) != 0;
# endif
# if defined(HAVE_AVX)
avx_available_ = (ecx & 0x10000000) != 0;
if (avx_available_) {
// There is supposed to be a __get_cpuid_count function, but this is all
// there is in my cpuid.h. It is a macro for an asm statement and cannot
// be used inside an if.
__cpuid_count(7, 0, eax, ebx, ecx, edx);
avx2_available_ = (ebx & 0x00000020) != 0;
avx512F_available_ = (ebx & 0x00010000) != 0;
avx512BW_available_ = (ebx & 0x40000000) != 0;
avx512VNNI_available_ = (ecx & 0x00000800) != 0;
}
# endif
}
# endif
}
# elif defined(_WIN32)
int cpuInfo[4];
int max_function_id;
__cpuid(cpuInfo, 0);
max_function_id = cpuInfo[0];
if (max_function_id >= 1) {
__cpuid(cpuInfo, 1);
# if defined(HAVE_SSE4_1)
sse_available_ = (cpuInfo[2] & 0x00080000) != 0;
# endif
# if defined(HAVE_AVX) || defined(HAVE_AVX2) || defined(HAVE_FMA)
if ((cpuInfo[2] & 0x08000000) && ((_xgetbv(0) & 6) == 6)) {
// OSXSAVE bit is set, XMM state and YMM state are fine.
# if defined(HAVE_FMA)
fma_available_ = (cpuInfo[2] & 0x00001000) != 0;
# endif
# if defined(HAVE_AVX)
avx_available_ = (cpuInfo[2] & 0x10000000) != 0;
# endif
# if defined(HAVE_AVX2)
if (max_function_id >= 7) {
__cpuid(cpuInfo, 7);
avx2_available_ = (cpuInfo[1] & 0x00000020) != 0;
avx512F_available_ = (cpuInfo[1] & 0x00010000) != 0;
avx512BW_available_ = (cpuInfo[1] & 0x40000000) != 0;
avx512VNNI_available_ = (cpuInfo[2] & 0x00000800) != 0;
}
# endif
}
# endif
}
# else
# error "I don't know how to test for SIMD with this compiler"
# endif
#endif
#if defined(HAVE_NEON) && !defined(__aarch64__)
# if defined(HAVE_ANDROID_GETCPUFAMILY)
{
AndroidCpuFamily family = android_getCpuFamily();
if (family == ANDROID_CPU_FAMILY_ARM)
neon_available_ = (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON);
}
# elif defined(HAVE_GETAUXVAL)
neon_available_ = getauxval(AT_HWCAP) & HWCAP_NEON;
# elif defined(HAVE_ELF_AUX_INFO)
unsigned long hwcap = 0;
elf_aux_info(AT_HWCAP, &hwcap, sizeof hwcap);
neon_available_ = hwcap & HWCAP_NEON;
# endif
#endif
#if defined(HAVE_RVV)
# if defined(HAVE_GETAUXVAL)
const unsigned long hwcap = getauxval(AT_HWCAP);
rvv_available_ = hwcap & HWCAP_RV('V');
# elif defined(HAVE_ELF_AUX_INFO)
unsigned long hwcap = 0;
elf_aux_info(AT_HWCAP, &hwcap, sizeof hwcap);
rvv_available_ = hwcap & HWCAP_RV('V');
# endif
#endif
// Select code for calculation of dot product based on autodetection.
if (false) {
// This is a dummy to support conditional compilation.
#if defined(HAVE_AVX512F)
} else if (avx512F_available_) {
// AVX512F detected.
SetDotProduct(DotProductAVX512F, &IntSimdMatrix::intSimdMatrixAVX2);
#endif
#if defined(HAVE_AVX2)
} else if (avx2_available_) {
// AVX2 detected.
SetDotProduct(DotProductAVX, &IntSimdMatrix::intSimdMatrixAVX2);
#endif
#if defined(HAVE_AVX)
} else if (avx_available_) {
// AVX detected.
SetDotProduct(DotProductAVX, &IntSimdMatrix::intSimdMatrixSSE);
#endif
#if defined(HAVE_SSE4_1)
} else if (sse_available_) {
// SSE detected.
SetDotProduct(DotProductSSE, &IntSimdMatrix::intSimdMatrixSSE);
#endif
#if defined(HAVE_NEON) || defined(__aarch64__)
} else if (neon_available_) {
// NEON detected.
SetDotProduct(DotProductNEON, &IntSimdMatrix::intSimdMatrixNEON);
#endif
#if defined(HAVE_RVV)
} else if (rvv_available_) {
SetDotProduct(DotProductGeneric, &IntSimdMatrix::intSimdMatrixRVV);
#endif
}
const char *dotproduct_env = getenv("DOTPRODUCT");
if (dotproduct_env != nullptr) {
// Override automatic settings by value from environment variable.
dotproduct = dotproduct_env;
Update();
}
}
void SIMDDetect::Update() {
// Select code for calculation of dot product based on the
// value of the config variable if that value is not empty.
const char *dotproduct_method = "generic";
if (dotproduct == "auto") {
// Automatic detection. Nothing to be done.
} else if (dotproduct == "generic") {
// Generic code selected by config variable.
SetDotProduct(DotProductGeneric);
dotproduct_method = "generic";
} else if (dotproduct == "native") {
// Native optimized code selected by config variable.
SetDotProduct(DotProductNative, IntSimdMatrix::intSimdMatrix);
dotproduct_method = "native";
#if defined(HAVE_AVX2)
} else if (dotproduct == "avx2") {
// AVX2 selected by config variable.
SetDotProduct(DotProductAVX, &IntSimdMatrix::intSimdMatrixAVX2);
dotproduct_method = "avx2";
#endif
#if defined(HAVE_AVX)
} else if (dotproduct == "avx") {
// AVX selected by config variable.
SetDotProduct(DotProductAVX, &IntSimdMatrix::intSimdMatrixSSE);
dotproduct_method = "avx";
#endif
#if defined(HAVE_FMA)
} else if (dotproduct == "fma") {
// FMA selected by config variable.
SetDotProduct(DotProductFMA, IntSimdMatrix::intSimdMatrix);
dotproduct_method = "fma";
#endif
#if defined(HAVE_SSE4_1)
} else if (dotproduct == "sse") {
// SSE selected by config variable.
SetDotProduct(DotProductSSE, &IntSimdMatrix::intSimdMatrixSSE);
dotproduct_method = "sse";
#endif
#if defined(HAVE_FRAMEWORK_ACCELERATE)
} else if (dotproduct == "accelerate") {
SetDotProduct(DotProductAccelerate, IntSimdMatrix::intSimdMatrix);
#endif
#if defined(HAVE_NEON) || defined(__aarch64__)
} else if (dotproduct == "neon" && neon_available_) {
// NEON selected by config variable.
SetDotProduct(DotProductNEON, &IntSimdMatrix::intSimdMatrixNEON);
dotproduct_method = "neon";
#endif
} else if (dotproduct == "std::inner_product") {
// std::inner_product selected by config variable.
SetDotProduct(DotProductStdInnerProduct, IntSimdMatrix::intSimdMatrix);
dotproduct_method = "std::inner_product";
} else {
// Unsupported value of config variable.
tprintf("Warning, ignoring unsupported config variable value: dotproduct=%s\n",
dotproduct.c_str());
tprintf(
"Supported values for dotproduct: auto generic native"
#if defined(HAVE_AVX2)
" avx2"
#endif
#if defined(HAVE_AVX)
" avx"
#endif
#if defined(HAVE_FMA)
" fma"
#endif
#if defined(HAVE_SSE4_1)
" sse"
#endif
#if defined(HAVE_FRAMEWORK_ACCELERATE)
" accelerate"
#endif
" std::inner_product.\n");
}
dotproduct.set_value(dotproduct_method);
}
} // namespace tesseract