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| author | Peter Lieven <pl@kamp.de> | 2013-03-26 10:58:33 +0100 |
|---|---|---|
| committer | Juan Quintela <quintela@redhat.com> | 2013-03-26 13:32:32 +0100 |
| commit | 56ded708ec38e4cb75a7c7357480ca34c0dc6875 (patch) | |
| tree | 5819b3f8f66612df3b1ad07ef74e5286c89fb780 /util | |
| parent | 41a259bd2b1796ddabdae600ee539269a7ddb6a5 (diff) | |
| download | qemu-56ded708ec38e4cb75a7c7357480ca34c0dc6875.zip qemu-56ded708ec38e4cb75a7c7357480ca34c0dc6875.tar.gz qemu-56ded708ec38e4cb75a7c7357480ca34c0dc6875.tar.bz2 | |
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: Peter Lieven <pl@kamp.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'util')
| -rw-r--r-- | util/cutils.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/util/cutils.c b/util/cutils.c index 0696a3b..5024253 100644 --- a/util/cutils.c +++ b/util/cutils.c @@ -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); |