Commit 2250d3a2 authored by Richard Henderson's avatar Richard Henderson Committed by Paolo Bonzini
Browse files

cutils: Remove aarch64 buffer zero checking 



The revised integer version is 4 times faster than the neon version
on an AppliedMicro Mustang.  Even with hand scheduling and additional
unrolling I cannot make any neon version run as fast as the integer.

Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 5e33a872

util/bufferiszero.c

+0 −15
Original line number Diff line number Diff line
@@ -200,21 +200,6 @@ static bool select_accel_fn(const void *buf, size_t len) 
    return buffer_zero_int(buf, len);

}



#elif defined(__aarch64__)

#include "arm_neon.h"



#define DO_NONZERO(X)  (vgetq_lane_u64((X), 0) | vgetq_lane_u64((X), 1))

ACCEL_BUFFER_ZERO(buffer_zero_neon, 128, uint64x2_t, DO_NONZERO)



static bool select_accel_fn(const void *buf, size_t len)

{

    uintptr_t ibuf = (uintptr_t)buf;

    if (len % 128 == 0 && ibuf % sizeof(uint64x2_t) == 0) {

        return buffer_zero_neon(buf, len);

    }

    return buffer_zero_int(buf, len);

}



#else

#define select_accel_fn  buffer_zero_int

#endif