avx2_test.c

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <err.h>

#define PAGESIZE 4096
#define DISKS 4

typedef unsigned char u8;
typedef unsigned long u64;

static const struct raid6_avx2_constants {
        u64 x1d[4];
} raid6_avx2_constants __attribute__((aligned(32))) = {
        { 0x1d1d1d1d1d1d1d1dULL, 0x1d1d1d1d1d1d1d1dULL,
                  0x1d1d1d1d1d1d1d1dULL, 0x1d1d1d1d1d1d1d1dULL,},
};

static void raid6_avx21_gen_syndrome(int disks, size_t bytes, void **ptrs)
{
        u8 **dptr = (u8 **)ptrs;
        u8 *p, *q;
        int d, z, z0;

        z0 = disks - 3;         /* Highest data disk */
        p = dptr[z0+1];         /* XOR parity */
        q = dptr[z0+2];         /* RS syndrome */

        asm volatile("vmovdqa %0,%%ymm0" : : "m" (raid6_avx2_constants.x1d[0]));
        asm volatile("vpxor %ymm3,%ymm3,%ymm3");        /* Zero temp */

        for (d = 0; d < bytes; d += 32) {
                asm volatile("prefetchnta %0" : : "m" (dptr[z0][d]));
                asm volatile("vmovdqa %0,%%ymm2" : : "m" (dptr[z0][d]));/* P[0] */
                asm volatile("prefetchnta %0" : : "m" (dptr[z0-1][d]));
                asm volatile("vmovdqa %ymm2,%ymm4");/* Q[0] */
                asm volatile("vmovdqa %0,%%ymm6" : : "m" (dptr[z0-1][d]));
                for (z = z0-2; z >= 0; z--) {
                        asm volatile("prefetchnta %0" : : "m" (dptr[z][d]));
                        asm volatile("vpcmpgtb %ymm4,%ymm3,%ymm5");
                        asm volatile("vpaddb %ymm4,%ymm4,%ymm4");
                        asm volatile("vpand %ymm0,%ymm5,%ymm5");
                        asm volatile("vpxor %ymm5,%ymm4,%ymm4");
                        asm volatile("vpxor %ymm6,%ymm2,%ymm2");
                        asm volatile("vpxor %ymm6,%ymm4,%ymm4");
                        asm volatile("vmovdqa %0,%%ymm6" : : "m" (dptr[z][d]));
                }
                asm volatile("vpcmpgtb %ymm4,%ymm3,%ymm5");
                asm volatile("vpaddb %ymm4,%ymm4,%ymm4");
                asm volatile("vpand %ymm0,%ymm5,%ymm5");
                asm volatile("vpxor %ymm5,%ymm4,%ymm4");
                asm volatile("vpxor %ymm6,%ymm2,%ymm2");
                asm volatile("vpxor %ymm6,%ymm4,%ymm4");

                asm volatile("vmovntdq %%ymm2,%0" : "=m" (p[d]));
                asm volatile("vpxor %ymm2,%ymm2,%ymm2");
                asm volatile("vmovntdq %%ymm4,%0" : "=m" (q[d]));
                asm volatile("vpxor %ymm4,%ymm4,%ymm4");
        }

        asm volatile("sfence" : : : "memory");
}

static char *data[DISKS];

int main(void)
{
        int i;
        for (i = 0; i < DISKS; i++)
                if ((errno = posix_memalign((void **)&data[i], PAGESIZE, PAGESIZE))) {
                        err(EXIT_FAILURE, "posix_memalign() failed");
                }
        raid6_avx21_gen_syndrome(DISKS, PAGESIZE, (void **)data);
        exit(EXIT_SUCCESS);
}