From patchwork Thu Mar 21 15:57:31 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 229747 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 8F5FF2C0267 for ; Fri, 22 Mar 2013 03:03:34 +1100 (EST) Received: from localhost ([::1]:56663 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIhxk-0006uu-QQ for incoming@patchwork.ozlabs.org; Thu, 21 Mar 2013 12:03:32 -0400 Received: from eggs.gnu.org ([208.118.235.92]:38541) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIhsQ-0006g3-SA for qemu-devel@nongnu.org; Thu, 21 Mar 2013 11:58:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UIhsN-0002jG-Oo for qemu-devel@nongnu.org; Thu, 21 Mar 2013 11:58:02 -0400 Received: from [2a02:248:0:30:223:aeff:fefe:7f1c] (port=33563 helo=dns.kamp-intra.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIhsN-0002iy-JI for qemu-devel@nongnu.org; Thu, 21 Mar 2013 11:57:59 -0400 Received: from lieven-pc.kamp-intra.net (lieven-pc.kamp-intra.net [172.21.12.60]) by dns.kamp-intra.net (Postfix) with ESMTP id 069D0206AD; Thu, 21 Mar 2013 16:57:59 +0100 (CET) Received: by lieven-pc.kamp-intra.net (Postfix, from userid 1000) id B0C925FCAE; Thu, 21 Mar 2013 16:58:09 +0100 (CET) From: Peter Lieven To: qemu-devel@nongnu.org Date: Thu, 21 Mar 2013 16:57:31 +0100 Message-Id: <1363881457-14814-4-git-send-email-pl@kamp.de> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1363881457-14814-1-git-send-email-pl@kamp.de> References: <1363881457-14814-1-git-send-email-pl@kamp.de> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 2a02:248:0:30:223:aeff:fefe:7f1c Cc: kwolf@redhat.com, pbonzini@redhat.com, Peter Lieven Subject: [Qemu-devel] [PATCHv3 3/9] buffer_is_zero: use vector optimizations if possible X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org performance gain on SSE2 is approx. 20-25%. altivec is not tested. performance for unsigned long arithmetic is unchanged. Signed-off-by: Peter Lieven Reviewed-by: Eric Blake --- util/cutils.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/util/cutils.c b/util/cutils.c index 6d079ac..52205a2 100644 --- a/util/cutils.c +++ b/util/cutils.c @@ -210,6 +210,11 @@ 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);