From patchwork Tue Mar 12 10:51:43 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 226932 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 04EA72C0099 for ; Tue, 12 Mar 2013 22:08:39 +1100 (EST) Received: from localhost ([::1]:32982 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UFN4O-0001zJ-Jy for incoming@patchwork.ozlabs.org; Tue, 12 Mar 2013 07:08:36 -0400 Received: from eggs.gnu.org ([208.118.235.92]:59963) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UFN46-0001xg-2D for qemu-devel@nongnu.org; Tue, 12 Mar 2013 07:08:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UFN42-0007yn-PM for qemu-devel@nongnu.org; Tue, 12 Mar 2013 07:08:18 -0400 Received: from ssl.dlhnet.de ([91.198.192.8]:43774 helo=ssl.dlh.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UFN42-0007yi-JV for qemu-devel@nongnu.org; Tue, 12 Mar 2013 07:08:14 -0400 Received: from localhost (localhost [127.0.0.1]) by ssl.dlh.net (Postfix) with ESMTP id 69D5E144081; Tue, 12 Mar 2013 11:51:44 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at ssl.dlh.net Received: from ssl.dlh.net ([127.0.0.1]) by localhost (ssl.dlh.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id JiB3Jp-VIzWa; Tue, 12 Mar 2013 11:51:44 +0100 (CET) Received: from [172.21.12.60] (unknown [82.141.1.226]) by ssl.dlh.net (Postfix) with ESMTPSA id DAA7A144FC1; Tue, 12 Mar 2013 11:51:41 +0100 (CET) Message-ID: <513F08BF.4040209@dlhnet.de> Date: Tue, 12 Mar 2013 11:51:43 +0100 From: Peter Lieven User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130221 Thunderbird/17.0.3 MIME-Version: 1.0 To: "qemu-devel@nongnu.org" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 91.198.192.8 Cc: peter.maydell@linaro.org, Paolo Bonzini , Kevin Wolf , Stefan Hajnoczi Subject: [Qemu-devel] [RFC] optimize is_dup_page for zero pages 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 Hi, a second patch to optimize live migration. I have generated some artifical load testing for zero pages. Ordinary dup or non dup pages are not affected. savings for zero pages (test case): non SSE2: 30s -> 26s SSE2: 27s -> 21s optionally I would suggest optimizing buffer_is_zero to use SSE2 if addr is 16 byte aligned and length is 128 byte aligned. in this case bdrv functions could also benefit from it. Peter diff --git a/arch_init.c b/arch_init.c index 98e2bc6..e1051e6 100644 --- a/arch_init.c +++ b/arch_init.c @@ -164,9 +164,37 @@ int qemu_read_default_config_files(bool userconfig) return 0; } -static int is_dup_page(uint8_t *page) +#if __SSE2__ +static int is_zero_page_sse2(u_int8_t *page) { VECTYPE *p = (VECTYPE *)page; + VECTYPE zero = _mm_setzero_si128(); + int i; + for (i = 0; i < (TARGET_PAGE_SIZE / sizeof(VECTYPE)); i+=8) { + VECTYPE tmp0 = _mm_or_si128(p[i+0],p[i+1]); + VECTYPE tmp1 = _mm_or_si128(p[i+2],p[i+3]); + VECTYPE tmp2 = _mm_or_si128(p[i+4],p[i+5]); + VECTYPE tmp3 = _mm_or_si128(p[i+6],p[i+7]); + VECTYPE tmp01 = _mm_or_si128(tmp0,tmp1); + VECTYPE tmp23 = _mm_or_si128(tmp2,tmp3); + if (!ALL_EQ(_mm_or_si128(tmp01,tmp23), zero)) { + return 0; + } + } + return 1; +} +#endif + +static int is_dup_page(u_int8_t *page) { + if (!page[0]) { +#if __SSE2__ + return is_zero_page_sse2(page); +#else + return buffer_is_zero(page, TARGET_PAGE_SIZE); +#endif + } + + VECTYPE *p = (VECTYPE *)page; VECTYPE val = SPLAT(page); int i;