Improve the performance of zasum and casum with AVX512 intrinsic

Author: xiegengxin

kernel/x86_64/KERNEL.SKYLAKEX

@@ -27,3 +27,6 @@ ZGEMMKERNEL    =  zgemm_kernel_4x2_skylakex.c
 
 CSCALKERNEL    = ../arm/zscal.c
 ZSCALKERNEL    = ../arm/zscal.c
+
+CASUMKERNEL = casum.c
+ZASUMKERNEL = zasum.c

kernel/x86_64/casum.c

@@ -0,0 +1,144 @@
+#include "common.h"
+
+#ifndef ABS_K
+#define ABS_K(a) ((a) > 0 ? (a) : (-(a)))
+#endif
+
+#if defined(SKYLAKEX)
+#include "casum_microk_skylakex-2.c"
+#endif
+
+#ifndef HAVE_CASUM_KERNEL
+static FLOAT casum_kernel(BLASLONG n, FLOAT *x1)
+{
+
+    BLASLONG i=0;
+    BLASLONG n_8 = n & -8;
+    FLOAT *x = x1;
+    FLOAT temp0, temp1, temp2, temp3;
+    FLOAT temp4, temp5, temp6, temp7;
+    FLOAT sum0 = 0.0;
+    FLOAT sum1 = 0.0;
+    FLOAT sum2 = 0.0;
+    FLOAT sum3 = 0.0;
+    FLOAT sum4 = 0.0;
+    
+    while (i < n_8) {
+        temp0 = ABS_K(x[0]);
+        temp1 = ABS_K(x[1]);
+        temp2 = ABS_K(x[2]);
+        temp3 = ABS_K(x[3]);
+        temp4 = ABS_K(x[4]);
+        temp5 = ABS_K(x[5]);
+        temp6 = ABS_K(x[6]);
+        temp7 = ABS_K(x[7]);
+        
+        sum0 += temp0;
+        sum1 += temp1;
+        sum2 += temp2;
+        sum3 += temp3;
+        
+        sum0 += temp4;
+        sum1 += temp5;
+        sum2 += temp6;
+        sum3 += temp7;
+        
+        x+=8;
+        i+=4;
+    }
+
+     while (i < n) {
+        sum4 += (ABS_K(x1[0]) + ABS_K(x1[1]));
+        x1 += 2;
+        i++;
+     }
+
+    return sum0+sum1+sum2+sum3+sum4;
+}
+
+#endif
+
+static FLOAT asum_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x)
+{
+    BLASLONG i = 0;
+    BLASLONG ip = 0;
+    BLASLONG inc_x2;
+    FLOAT sumf = 0.0;
+
+    if (n <= 0 || inc_x <= 0) return(sumf);
+    if (inc_x == 1) {
+        sumf = casum_kernel(n, x);
+    }
+    else {
+        inc_x2 = 2 * inc_x;
+
+        while (i < n) {
+            sumf += ABS_K(x[ip]) + ABS_K(x[ip + 1]);
+            ip += inc_x2;
+            i++;
+        }
+    }
+
+    return(sumf);
+}
+
+#if defined(SMP)
+static int asum_thread_function(BLASLONG n, 
+        BLASLONG dummy0, BLASLONG dummy1, FLOAT dummy2,
+        FLOAT *x, BLASLONG inc_x,
+        FLOAT * dummy3, BLASLONG dummy4,
+        FLOAT * result, BLASLONG dummy5)
+{
+    *(FLOAT *) result = asum_compute(n, x, inc_x);
+    return 0;
+}
+
+extern int blas_level1_thread_with_value(int mode, 
+        BLASLONG m, BLASLONG n, BLASLONG k, void * alpha,
+        void *a, BLASLONG lda, 
+        void *b, BLASLONG ldb,
+        void *c, BLASLONG ldc,
+        int (*function)(),
+        int nthread);
+#endif
+
+FLOAT CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
+{
+#if defined(SMP)
+    int nthreads;
+    FLOAT dummy_alpha[2];
+#endif
+    FLOAT sumf = 0.0;
+
+#if defined(SMP)
+    int num_cpu = num_cpu_avail(1);
+    if (n <= 10000 || inc_x <= 0)
+        nthreads = 1;
+    else
+        nthreads = num_cpu < n/10000 ? num_cpu : n/10000;
+    
+    if (nthreads == 1) {
+        sumf = asum_compute(n, x, inc_x);
+    }
+    else {
+        int mode, i;
+        char result[MAX_CPU_NUMBER * sizeof(double) *2];
+        FLOAT *ptr;
+#if !defined(DOUBLE)
+        mode = BLAS_SINGLE | BLAS_COMPLEX;
+#else
+        mode = BLAS_DOUBLE | BLAS_COMPLEX;
+#endif
+        blas_level1_thread_with_return_value(mode, n, 0, 0, dummy_alpha, x, inc_x, 
+                NULL, 0, result, 0, (void *)asum_thread_function, nthreads);
+        ptr = (FLOAT *)result;
+        for (i = 0; i < nthreads; i++) {
+            sumf += (*ptr);
+            ptr = (FLOAT *)(((char *)ptr) + sizeof(double) *2);
+        }
+    }
+#else
+    sumf = asum_compute(n, x, inc_x);
+#endif
+    return(sumf);
+}