Optimize gemv_n_sve kernel

kernel/arm64/KERNEL.ARMV8SVE

@@ -74,7 +74,7 @@ DSCALKERNEL  = scal.S
 CSCALKERNEL  = zscal.S
 ZSCALKERNEL  = zscal.S
 
-SGEMVNKERNEL = gemv_n.S
+SGEMVNKERNEL = gemv_n_sve.c
 DGEMVNKERNEL = gemv_n.S
 CGEMVNKERNEL = zgemv_n.S
 ZGEMVNKERNEL = zgemv_n.S

kernel/arm64/gemv_n_sve.c

@@ -1,5 +1,5 @@
 /***************************************************************************
-Copyright (c) 2024, The OpenBLAS Project
+Copyright (c) 2024-2025, The OpenBLAS Project
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
@@ -59,23 +59,82 @@ int CNAME(BLASLONG m, BLASLONG n, BLASLONG dummy1, FLOAT alpha, FLOAT *a, BLASLO
   a_ptr = a;
 
   if (inc_y == 1) {
+    BLASLONG width = n / 3;
     uint64_t sve_size = SV_COUNT();
-    for (j = 0; j < n; j++) {
-      SV_TYPE temp_vec = SV_DUP(alpha * x[ix]);
-      i = 0;
-      svbool_t pg = SV_WHILE(i, m);
-      while (svptest_any(SV_TRUE(), pg)) {
-        SV_TYPE a_vec = svld1(pg, a_ptr + i);
+    svbool_t pg_true = SV_TRUE();
+    svbool_t pg = SV_WHILE(0, m % sve_size);
+
+    FLOAT *a0_ptr = a + lda * width * 0;
+    FLOAT *a1_ptr = a + lda * width * 1;
+    FLOAT *a2_ptr = a + lda * width * 2;
+
+    for (j = 0; j < width; j++) {
+      for (i = 0; (i + sve_size - 1) < m; i += sve_size) {
+        ix = j * inc_x;
+
+        SV_TYPE x0_vec = SV_DUP(alpha * x[ix + (inc_x * width * 0)]);
+        SV_TYPE x1_vec = SV_DUP(alpha * x[ix + (inc_x * width * 1)]);
+        SV_TYPE x2_vec = SV_DUP(alpha * x[ix + (inc_x * width * 2)]);
+
+        SV_TYPE a00_vec = svld1(pg_true, a0_ptr + i);
+        SV_TYPE a01_vec = svld1(pg_true, a1_ptr + i);
+        SV_TYPE a02_vec = svld1(pg_true, a2_ptr + i);
+
+        SV_TYPE y_vec = svld1(pg_true, y + i);
+        y_vec = svmla_lane(y_vec, a00_vec, x0_vec, 0);
+        y_vec = svmla_lane(y_vec, a01_vec, x1_vec, 0);
+        y_vec = svmla_lane(y_vec, a02_vec, x2_vec, 0);
+
+        svst1(pg_true, y + i, y_vec);
+      }
+
+      if (i < m) {
+        SV_TYPE x0_vec = SV_DUP(alpha * x[ix + (inc_x * width * 0)]);
+        SV_TYPE x1_vec = SV_DUP(alpha * x[ix + (inc_x * width * 1)]);
+        SV_TYPE x2_vec = SV_DUP(alpha * x[ix + (inc_x * width * 2)]);
+
+        SV_TYPE a00_vec = svld1(pg, a0_ptr + i);
+        SV_TYPE a01_vec = svld1(pg, a1_ptr + i);
+        SV_TYPE a02_vec = svld1(pg, a2_ptr + i);
+
         SV_TYPE y_vec = svld1(pg, y + i);
-        y_vec = svmla_x(pg, y_vec, temp_vec, a_vec);
+        y_vec = svmla_m(pg, y_vec, a00_vec, x0_vec);
+        y_vec = svmla_m(pg, y_vec, a01_vec, x1_vec);
+        y_vec = svmla_m(pg, y_vec, a02_vec, x2_vec);
+
+        ix += inc_x;
+
         svst1(pg, y + i, y_vec);
-        i += sve_size;
-        pg = SV_WHILE(i, m);
       }
+
+      a0_ptr += lda;
+      a1_ptr += lda;
+      a2_ptr += lda;
+    }
+
+    a_ptr = a2_ptr;
+    for (j = width * 3; j < n; j++) {
+      ix = j * inc_x;
+      for (i = 0; (i + sve_size - 1) < m; i += sve_size) {
+        SV_TYPE y_vec = svld1(pg_true, y + i);
+        SV_TYPE x_vec = SV_DUP(alpha * x[(ix)]);
+        SV_TYPE a_vec = svld1(pg_true, a_ptr + i);
+        y_vec = svmla_x(pg_true, y_vec, a_vec, x_vec);
+        svst1(pg_true, y + i, y_vec);
+      }
+
+      if (i < m) {
+        SV_TYPE y_vec = svld1(pg, y + i);
+        SV_TYPE x_vec = SV_DUP(alpha * x[(ix)]);
+        SV_TYPE a_vec = svld1(pg, a_ptr + i);
+        y_vec = svmla_m(pg, y_vec, a_vec, x_vec);
+        svst1(pg, y + i, y_vec);
+      }
+
       a_ptr += lda;
       ix += inc_x;
     }
-    return(0);
+    return (0);
   }
 
   for (j = 0; j < n; j++) {
@@ -89,4 +148,4 @@ int CNAME(BLASLONG m, BLASLONG n, BLASLONG dummy1, FLOAT alpha, FLOAT *a, BLASLO
     ix += inc_x;
   }
   return (0);
-}
+}