Remove misleading benchmarks

Author: AntoinePrv

cpp/src/arrow/util/byte_stream_split_internal.h

@@ -355,13 +355,9 @@ template <int kNumStreams>
 void ByteStreamSplitEncodeAvx2(const uint8_t* raw_values, int width,
                                const int64_t num_values, uint8_t* output_buffer_raw) {
   assert(width == kNumStreams);
-  static_assert(kNumStreams == 4 || kNumStreams == 8, "Invalid number of streams.");
+  static_assert(kNumStreams == 4, "Invalid number of streams.");
   constexpr int kBlockSize = sizeof(__m256i) * kNumStreams;
 
-  if constexpr (kNumStreams == 8)  // Back to SSE, currently no path for double.
-    return ByteStreamSplitEncodeSimd128<kNumStreams>(raw_values, width, num_values,
-                                                     output_buffer_raw);
-
   const int64_t size = num_values * kNumStreams;
   if (size < kBlockSize)  // Back to SSE for small size
     return ByteStreamSplitEncodeSimd128<kNumStreams>(raw_values, width, num_values,
@@ -449,7 +445,7 @@ void inline ByteStreamSplitEncodeSimd(const uint8_t* raw_values, int width,
                                       uint8_t* output_buffer_raw) {
 #  if defined(ARROW_HAVE_AVX2)
   // Not implemented
-  if constexpr (kNumStreams == 2) {
+  if constexpr (kNumStreams == 2 || kNumStreams == 8) {
     return ByteStreamSplitEncodeSimd128<kNumStreams>(raw_values, width, num_values,
                                                      output_buffer_raw);
   } else {

cpp/src/parquet/encoding_benchmark.cc

@@ -548,11 +548,6 @@ BENCHMARK(BM_ByteStreamSplitEncode_Double_Sse2)->Apply(ByteStreamSplitApply);
 #endif
 
 #if defined(ARROW_HAVE_AVX2)
-static void BM_ByteStreamSplitDecode_Int16_Avx2(benchmark::State& state) {
-  BM_ByteStreamSplitDecode<int16_t>(
-      state, ::arrow::util::internal::ByteStreamSplitDecodeAvx2<sizeof(int16_t)>);
-}
-
 static void BM_ByteStreamSplitDecode_Float_Avx2(benchmark::State& state) {
   BM_ByteStreamSplitDecode<float>(
       state, ::arrow::util::internal::ByteStreamSplitDecodeAvx2<sizeof(float)>);
@@ -563,21 +558,11 @@ static void BM_ByteStreamSplitDecode_Double_Avx2(benchmark::State& state) {
       state, ::arrow::util::internal::ByteStreamSplitDecodeAvx2<sizeof(double)>);
 }
 
-static void BM_ByteStreamSplitEncode_Int16_Avx2(benchmark::State& state) {
-  BM_ByteStreamSplitEncode<int16_t>(
-      state, ::arrow::util::internal::ByteStreamSplitEncodeAvx2<sizeof(int16_t)>);
-}
-
 static void BM_ByteStreamSplitEncode_Float_Avx2(benchmark::State& state) {
   BM_ByteStreamSplitEncode<float>(
       state, ::arrow::util::internal::ByteStreamSplitEncodeAvx2<sizeof(float)>);
 }
 
-static void BM_ByteStreamSplitEncode_Double_Avx2(benchmark::State& state) {
-  BM_ByteStreamSplitEncode<double>(
-      state, ::arrow::util::internal::ByteStreamSplitEncodeAvx2<sizeof(double)>);
-}
-
 BENCHMARK(BM_ByteStreamSplitDecode_Int16_Avx2)->Apply(ByteStreamSplitApply);
 BENCHMARK(BM_ByteStreamSplitDecode_Float_Avx2)->Apply(ByteStreamSplitApply);
 BENCHMARK(BM_ByteStreamSplitDecode_Double_Avx2)->Apply(ByteStreamSplitApply);