Support VNNI on 256bit vectors

due to downclocking on current chips (tested up to cascade lake)
supporting avx512 and vnni512, it is better to use avx2 or vnni256
in multithreaded (in particular hyperthreaded) engine use.
In single threaded use, the picture is different.

gcc compilation for vnni256 requires a toolchain for gcc >= 9.

closes https://github.com/official-stockfish/Stockfish/pull/3038

No functional change

diff --git a/.travis.yml b/.travis.yml
index a029c4fc818946063ae637a1617a1c58f5099757..c1e6d6df41faf8733d3700c07cc997dd9c5adad7 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -77,8 +77,10 @@ script:
   # compile only for some more advanced architectures (might not run in travis)
   - make clean && make -j2 ARCH=x86-64-avx2 build
   - make clean && make -j2 ARCH=x86-64-bmi2 build
-  # needs gcc 10 to compile
-  - if [[ "$COMPILER" != "g++-8" ]]; then make clean && make -j2 ARCH=x86-64-avx512 build; fi
+  - make clean && make -j2 ARCH=x86-64-avx512 build
+  - make clean && make -j2 ARCH=x86-64-vnni512 build
+  # requires gcc 9 or higher
+  - if [[ "$COMPILER" != "g++-8" ]]; make clean && make -j2 ARCH=x86-64-vnni256 build; fi
 
   #
   # Check perft and reproducible search

diff --git a/src/Makefile b/src/Makefile
index 3e1b7c351bc4dd5e7d90ea25f2c5c3202488d55d..228ea851f208154001cd3dcab5926d298ff240cb 100644 (file)
--- a/src/Makefile
+++ b/src/Makefile
@@ -75,7 +75,8 @@ endif
 # sse41 = yes/no      --- -msse4.1         --- Use Intel Streaming SIMD Extensions 4.1
 # avx2 = yes/no       --- -mavx2           --- Use Intel Advanced Vector Extensions 2
 # avx512 = yes/no     --- -mavx512bw       --- Use Intel Advanced Vector Extensions 512
-# vnni = yes/no       --- -mavx512vnni     --- Use Intel Vector Neural Network Instructions 512
+# vnni256 = yes/no    --- -mavx512vnni     --- Use Intel Vector Neural Network Instructions 256
+# vnni512 = yes/no    --- -mavx512vnni     --- Use Intel Vector Neural Network Instructions 512
 # neon = yes/no       --- -DUSE_NEON       --- Use ARM SIMD architecture
 #
 # Note that Makefile is space sensitive, so when adding new architectures
@@ -102,7 +103,8 @@ ssse3 = no
 sse41 = no
 avx2 = no
 avx512 = no
-vnni = no
+vnni256 = no
+vnni512 = no
 neon = no
 ARCH = x86-64-modern
 STRIP = strip
@@ -192,7 +194,18 @@ ifeq ($(findstring -avx512,$(ARCH)),-avx512)
        avx512 = yes
 endif
 
-ifeq ($(findstring -vnni,$(ARCH)),-vnni)
+ifeq ($(findstring -vnni256,$(ARCH)),-vnni256)
+       popcnt = yes
+       sse = yes
+       sse2 = yes
+       ssse3 = yes
+       sse41 = yes
+       avx2 = yes
+       pext = yes
+       vnni256 = yes
+endif
+
+ifeq ($(findstring -vnni512,$(ARCH)),-vnni512)
        popcnt = yes
        sse = yes
        sse2 = yes
@@ -201,7 +214,7 @@ ifeq ($(findstring -vnni,$(ARCH)),-vnni)
        avx2 = yes
        pext = yes
        avx512 = yes
-       vnni = yes
+       vnni512 = yes
 endif
 
 ifeq ($(sse),yes)
@@ -500,7 +513,14 @@ ifeq ($(avx512),yes)
        endif
 endif
 
-ifeq ($(vnni),yes)
+ifeq ($(vnni256),yes)
+       CXXFLAGS += -DUSE_VNNI
+       ifeq ($(comp),$(filter $(comp),gcc clang mingw))
+               CXXFLAGS += -mavx512vnni -mavx512dq -mavx512vl -mprefer-vector-width=256
+       endif
+endif
+
+ifeq ($(vnni512),yes)
        CXXFLAGS += -DUSE_VNNI
        ifeq ($(comp),$(filter $(comp),gcc clang mingw))
                CXXFLAGS += -mavx512vnni -mavx512dq -mavx512vl
@@ -623,7 +643,8 @@ help:
        @echo ""
        @echo "Supported archs:"
        @echo ""
-       @echo "x86-64-vnni             > x86 64-bit with vnni support"
+       @echo "x86-64-vnni512          > x86 64-bit with vnni support 512bit wide"
+       @echo "x86-64-vnni256          > x86 64-bit with vnni support 256bit wide"
        @echo "x86-64-avx512           > x86 64-bit with avx512 support"
        @echo "x86-64-bmi2             > x86 64-bit with bmi2 support"
        @echo "x86-64-avx2             > x86 64-bit with avx2 support"
@@ -767,7 +788,8 @@ config-sanity:
        @echo "sse41: '$(sse41)'"
        @echo "avx2: '$(avx2)'"
        @echo "avx512: '$(avx512)'"
-       @echo "vnni: '$(vnni)'"
+       @echo "vnni256: '$(vnni256)'"
+       @echo "vnni512: '$(vnni512)'"
        @echo "neon: '$(neon)'"
        @echo ""
        @echo "Flags:"
@@ -794,7 +816,8 @@ config-sanity:
        @test "$(sse41)" = "yes" || test "$(sse41)" = "no"
        @test "$(avx2)" = "yes" || test "$(avx2)" = "no"
        @test "$(avx512)" = "yes" || test "$(avx512)" = "no"
-       @test "$(vnni)" = "yes" || test "$(vnni)" = "no"
+       @test "$(vnni256)" = "yes" || test "$(vnni256)" = "no"
+       @test "$(vnni512)" = "yes" || test "$(vnni512)" = "no"
        @test "$(neon)" = "yes" || test "$(neon)" = "no"
        @test "$(comp)" = "gcc" || test "$(comp)" = "icc" || test "$(comp)" = "mingw" || test "$(comp)" = "clang" \
        || test "$(comp)" = "armv7a-linux-androideabi16-clang"  || test "$(comp)" = "aarch64-linux-android21-clang"

diff --git a/src/nnue/layers/affine_transform.h b/src/nnue/layers/affine_transform.h
index 7ac5a1c099f60574c101dca05e2034ed68fce30e..94d0b5a9494644e574cd111104943d18667c9196 100644 (file)
--- a/src/nnue/layers/affine_transform.h
+++ b/src/nnue/layers/affine_transform.h
@@ -85,8 +85,10 @@ namespace Eval::NNUE::Layers {
 
   #elif defined(USE_AVX2)
       constexpr IndexType kNumChunks = kPaddedInputDimensions / kSimdWidth;
-      const __m256i kOnes = _mm256_set1_epi16(1);
       const auto input_vector = reinterpret_cast<const __m256i*>(input);
+  #if !defined(USE_VNNI)
+      const __m256i kOnes = _mm256_set1_epi16(1);
+  #endif
 
   #elif defined(USE_SSE2)
       constexpr IndexType kNumChunks = kPaddedInputDimensions / kSimdWidth;
@@ -145,9 +147,13 @@ namespace Eval::NNUE::Layers {
         __m256i sum = _mm256_setzero_si256();
         const auto row = reinterpret_cast<const __m256i*>(&weights_[offset]);
         for (IndexType j = 0; j < kNumChunks; ++j) {
+  #if defined(USE_VNNI)
+          sum = _mm256_dpbusd_epi32(sum, _mm256_loadA_si256(&input_vector[j]), _mm256_load_si256(&row[j]));
+  #else
           __m256i product = _mm256_maddubs_epi16(_mm256_loadA_si256(&input_vector[j]), _mm256_load_si256(&row[j]));
           product = _mm256_madd_epi16(product, kOnes);
           sum = _mm256_add_epi32(sum, product);
+  #endif
         }
         __m128i sum128 = _mm_add_epi32(_mm256_castsi256_si128(sum), _mm256_extracti128_si256(sum, 1));
         sum128 = _mm_add_epi32(sum128, _mm_shuffle_epi32(sum128, _MM_PERM_BADC));