Commit 56ded708 authored by Peter Lieven's avatar Peter Lieven Committed by Juan Quintela
Browse files

buffer_is_zero: use vector optimizations if possible 



performance gain on SSE2 is approx. 20-25%. altivec
is not tested. performance for unsigned long arithmetic
is unchanged.

Signed-off-by: default avatarPeter Lieven <pl@kamp.de>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarOrit Wasserman <owasserm@redhat.com>
Signed-off-by: default avatarJuan Quintela <quintela@redhat.com>
parent 41a259bd

util/cutils.c

+5 −0
Original line number Diff line number Diff line
@@ -215,6 +215,11 @@ bool buffer_is_zero(const void *buf, size_t len) 
    long d0, d1, d2, d3;

    const long * const data = buf;



    /* use vector optimized zero check if possible */

    if (can_use_buffer_find_nonzero_offset(buf, len)) {

        return buffer_find_nonzero_offset(buf, len) == len;

    }



    assert(len % (4 * sizeof(long)) == 0);

    len /= sizeof(long);