Optimized sgemv_t for small N based on AVX512

kernel/x86_64/sgemv_t_4.c

@@ -34,8 +34,11 @@ USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "sgemv_t_microk_bulldozer-4.c"
 #elif defined(SANDYBRIDGE)
 #include "sgemv_t_microk_sandy-4.c"
-#elif defined(HASWELL) || defined(ZEN) || defined (SKYLAKEX) || defined (COOPERLAKE)
+#elif defined(HASWELL) || defined(ZEN)
 #include "sgemv_t_microk_haswell-4.c"
+#elif defined (SKYLAKEX) || defined (COOPERLAKE)
+#include "sgemv_t_microk_haswell-4.c"
+#include "sgemv_t_microk_skylakex.c"
 #endif
 
 #if defined(STEAMROLLER) || defined(EXCAVATOR)
@@ -305,6 +308,37 @@ int CNAME(BLASLONG m, BLASLONG n, BLASLONG dummy1, FLOAT alpha, FLOAT *a, BLASLO
         if ( m < 1 ) return(0);
         if ( n < 1 ) return(0);
 
+	#ifdef HAVE_SGEMV_T_SKYLAKE_KERNEL
+    if (lda == m && n <= 16384 && m <= 8)
+    {
+        FLOAT * xbuffer_align = x;
+        FLOAT * ybuffer_align = y;
+
+        if (inc_x != 1) {
+            xbuffer_align = buffer;
+            for(BLASLONG i=0; i<m; i++) {
+                 xbuffer_align[i] = x[i*inc_x];
+            }
+        }
+
+        if (inc_y != 1) {
+            ybuffer_align = buffer + m;
+            for(BLASLONG i=0; i<n; i++) {
+                ybuffer_align[i] = y[i*inc_y];
+            }
+        }
+        sgemv_kernel_t(m, n , alpha, a, xbuffer_align, ybuffer_align);
+
+        if(inc_y != 1) {
+            for(BLASLONG i=0; i<n; i++) {
+                   y[i*inc_y] = ybuffer_align[i];
+            }
+        }
+        return(0);
+    }
+
+    #endif
+
 	xbuffer = buffer;
 	ytemp   = buffer + (m < NBMAX ? m : NBMAX);
 	

kernel/x86_64/sgemv_t_microk_skylakex.c

@@ -0,0 +1,60 @@
+/***************************************************************************
+Copyright (c) 2014, The OpenBLAS Project
+All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+1. Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in
+the documentation and/or other materials provided with the
+distribution.
+3. Neither the name of the OpenBLAS project nor the names of
+its contributors may be used to endorse or promote products
+derived from this software without specific prior written permission.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBLAS PROJECT OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*****************************************************************************/
+
+/* need a new enough GCC for avx512 support */
+#if (( defined(__GNUC__)  && __GNUC__   >= 6 && defined(__AVX512CD__)) || (defined(__clang__) && __clang_major__ >= 6))
+
+#define HAVE_SGEMV_T_SKYLAKE_KERNEL 1
+#include "common.h"
+#include <immintrin.h>
+#include "sgemv_t_microk_skylakex_template.c"
+
+//sgemv_t:
+// ----- m -----
+// |<-----------
+// |<-----------
+// n
+// |<-----------
+// |<-----------
+
+static int sgemv_kernel_t(BLASLONG m, BLASLONG n, float alpha, float *a, float *x, float *y)
+{    
+    switch(m) {
+        case 1:  sgemv_kernel_t_1(n, alpha, a, x, y); break;
+        case 2:  sgemv_kernel_t_2(n, alpha, a, x, y); break;
+        case 3:  sgemv_kernel_t_3(n, alpha, a, x, y); break;
+        case 4:  sgemv_kernel_t_4(n, alpha, a, x, y); break;
+        case 5:  sgemv_kernel_t_5(n, alpha, a, x, y); break;
+        case 6:  sgemv_kernel_t_6(n, alpha, a, x, y); break;
+        case 7:  sgemv_kernel_t_7(n, alpha, a, x, y); break;
+        case 8:  sgemv_kernel_t_8(n, alpha, a, x, y); break;
+        default: break;
+    }
+    return 0;
+}
+
+#endif